diff --git a/java-diff-utils/src/main/java/com/github/difflib/UnifiedDiffUtils.java b/java-diff-utils/src/main/java/com/github/difflib/UnifiedDiffUtils.java
index e926560d..727008db 100644
--- a/java-diff-utils/src/main/java/com/github/difflib/UnifiedDiffUtils.java
+++ b/java-diff-utils/src/main/java/com/github/difflib/UnifiedDiffUtils.java
@@ -420,11 +420,11 @@ private static void insertOrig(List<List<String>> diffList, List<String> result,
                 int end = nexMap.get("revRow") - 2;
                 insert(result, getOrigList(original, start, end));
             }
+            int start = map.get("orgRow") + map.get("orgDel") - 1;
+            start = start == -1 ? 0 : start;
             if (simb.contains("@@ -1,") && null == nexSimb && map.get("orgDel") != original.size()) {
-                insert(result, getOrigList(original, 0, original.size() - 1));
+                insert(result, getOrigList(original, start, original.size() - 1));
             } else if (null == nexSimb && (map.get("orgRow") + map.get("orgDel") - 1) < original.size()) {
-                int start = map.get("orgRow") + map.get("orgDel") - 1;
-                start = start == -1 ? 0 : start;
                 insert(result, getOrigList(original, start, original.size() - 1));
             }
         }
diff --git a/java-diff-utils/src/test/java/com/github/difflib/examples/OriginalAndDiffTest.java b/java-diff-utils/src/test/java/com/github/difflib/examples/OriginalAndDiffTest.java
index 7f2d3b29..17283b4d 100644
--- a/java-diff-utils/src/test/java/com/github/difflib/examples/OriginalAndDiffTest.java
+++ b/java-diff-utils/src/test/java/com/github/difflib/examples/OriginalAndDiffTest.java
@@ -31,6 +31,21 @@ public void testGenerateOriginalAndDiff()  {
         System.out.println(originalAndDiff.stream().collect(joining("\n")));
     }
 
+    @Test
+    public void testGenerateOriginalAndDiffFirstLineChange()  {
+        List<String> origLines = null;
+        List<String> revLines = null;
+        try {
+            origLines = fileToLines(TestConstants.MOCK_FOLDER + "issue_170_original.txt");
+            revLines = fileToLines(TestConstants.MOCK_FOLDER + "issue_170_revised.txt");
+        } catch (IOException e) {
+            fail(e.getMessage());
+        }
+
+        List<String> originalAndDiff = UnifiedDiffUtils.generateOriginalAndDiff(origLines, revLines);
+        System.out.println(originalAndDiff.stream().collect(joining("\n")));
+    }
+
     public static List<String> fileToLines(String filename) throws FileNotFoundException, IOException {
         List<String> lines = new ArrayList<>();
         String line = "";
diff --git a/java-diff-utils/src/test/resources/mocks/issue_170_original.txt b/java-diff-utils/src/test/resources/mocks/issue_170_original.txt
new file mode 100644
index 00000000..8aa703f0
--- /dev/null
+++ b/java-diff-utils/src/test/resources/mocks/issue_170_original.txt
@@ -0,0 +1,95 @@
+//According to the original text, an html will be generated by comparing the text
+public class generateDiffHtmlTest {
+    /**
+     * Here's a simple example of getting a nice html page based on the original text and the contrasted text,Read n1.txt and n2.txt of D disk, and finally generate an html file
+     *
+     */
+    @Test
+    public static void generateOriginalAndDiffDemo(){
+        List<String> origLines = getFileContent("D:\\n1.txt");
+        List<String> revLines =getFileContent("D:\\n2.txt");
+        List<String> originalAndDiff =UnifiedDiffUtils.generateOriginalAndDiff(origLines, revLines);
+        //System.out.println(originalAndDiff.size());
+        generateDiffHtml(originalAndDiff,"D:\\diff.html");
+    }
+
+    /**
+     * get file content
+     * @param filePath file path
+     */
+    public static List<String> getFileContent(String filePath) {
+        //origin
+        List<String> fileContent =null;
+        File file = new File(filePath);
+        try {
+            fileContent = Files.readAllLines(file.toPath());
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return fileContent;
+    }
+
+    /**
+     * The html file is generated by the difference diff between the two files, and the detailed content of the file comparison can be seen by opening the html file
+     *
+     */
+    public static void generateDiffHtml(List<String> diffString, String htmlPath) {
+        StringBuilder builder = new StringBuilder();
+        for (String line : diffString) {
+            builder.append(line);
+            builder.append("\n");
+        }
+        String githubCss = "https://cdnjs.cloudflare.com/ajax/libs/highlight.js/10.7.1/styles/github.min.css";
+        String diff2htmlCss = "https://cdn.jsdelivr.net/npm/diff2html/bundles/css/diff2html.min.css";
+        String diff2htmlJs = "https://cdn.jsdelivr.net/npm/diff2html/bundles/js/diff2html-ui.min.js";
+
+        String template = "<!DOCTYPE html>\n" +
+                "<html lang=\"en-us\">\n" +
+                "  <head>\n" +
+                "    <meta charset=\"utf-8\" />\n" +
+                "    <link rel=\"stylesheet\" href=\"" + githubCss + "\" />\n" +
+                "     <link rel=\"stylesheet\" type=\"text/css\" href=\"" + diff2htmlCss + "\" />\n" +
+                "    <script type=\"text/javascript\" src=\"" + diff2htmlJs + "\"></script>\n" +
+                "  </head>\n" +
+                "  <script>\n" +
+                "    const diffString = `\n" +
+                "temp\n" +
+                "`;\n" +
+                "\n" +
+                "\n" +
+                "     document.addEventListener('DOMContentLoaded', function () {\n" +
+                "      var targetElement = document.getElementById('myDiffElement');\n" +
+                "      var configuration = {\n" +
+                "        drawFileList: true,\n" +
+                "        fileListToggle: true,\n" +
+                "        fileListStartVisible: true,\n" +
+                "        fileContentToggle: true,\n" +
+                "        matching: 'lines',\n" +
+                "        outputFormat: 'side-by-side',\n" +
+                "        synchronisedScroll: true,\n" +
+                "        highlight: true,\n" +
+                "        renderNothingWhenEmpty: true,\n" +
+                "      };\n" +
+                "      var diff2htmlUi = new Diff2HtmlUI(targetElement, diffString, configuration);\n" +
+                "      diff2htmlUi.draw();\n" +
+                "      diff2htmlUi.highlightCode();\n" +
+                "    });\n" +
+                "  </script>\n" +
+                "  <body>\n" +
+                "    <div id=\"myDiffElement\"></div>\n" +
+                "  </body>\n" +
+                "</html>";
+        template = template.replace("temp", builder.toString());
+        FileWriter fileWriter = null;
+        try {
+            fileWriter = new FileWriter(htmlPath);
+            BufferedWriter buf = new BufferedWriter(fileWriter);
+            buf.write(template);
+            buf.close();
+            fileWriter.close();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+}
diff --git a/java-diff-utils/src/test/resources/mocks/issue_170_revised.txt b/java-diff-utils/src/test/resources/mocks/issue_170_revised.txt
new file mode 100644
index 00000000..7aa91dc2
--- /dev/null
+++ b/java-diff-utils/src/test/resources/mocks/issue_170_revised.txt
@@ -0,0 +1,114 @@
+package com.github.difflib.examples;
+
+import com.github.difflib.UnifiedDiffUtils;
+import org.junit.jupiter.api.Test;
+
+import java.io.BufferedWriter;
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.List;
+
+// According to the original text, an html will be generated by comparing the text.
+public class generateDiffHtmlTest {
+
+    /**
+     * Here's a simple example of getting a nice html page based on the original text and the contrasted text,
+     * Read n1.txt and n2.txt of D disk, and finally generate an html file
+     *
+     */
+    @Test
+    public static void generateOriginalAndDiffDemo(){
+        List<String> origLines = getFileContent("D:\\n1.txt");
+        List<String> revLines = getFileContent("D:\\n2.txt");
+        List<String> originalAndDiff =  UnifiedDiffUtils.generateOriginalAndDiff(origLines, revLines);
+
+        //generateDiffHtml
+        generateDiffHtml(originalAndDiff,"D:\\diff.html");
+    }
+
+    /**
+     * get file content
+     *
+     * @param filePath file path
+     */
+    public static List<String> getFileContent(String filePath) {
+        //原始文件
+        List<String> fileContent = null;
+        File file = new File(filePath);
+        try {
+            fileContent = Files.readAllLines(file.toPath());
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return fileContent;
+    }
+
+    /**
+     * The html file is generated by the difference diff between the two files,
+     * and the detailed content of the file comparison can be seen by opening the html file
+     *
+     * @param diffString The comparison result obtained by calling the above diffString method
+     * @param htmlPath   Generated html path，e.g:/user/var/mbos/ent/21231/diff.html
+     */
+    public static void generateDiffHtml(List<String> diffString, String htmlPath) {
+        StringBuilder builder = new StringBuilder();
+        for (String line : diffString) {
+            builder.append(line);
+            builder.append("\n");
+        }
+        String githubCss = "https://cdnjs.cloudflare.com/ajax/libs/highlight.js/10.7.1/styles/github.min.css";
+        String diff2htmlCss = "https://cdn.jsdelivr.net/npm/diff2html/bundles/css/diff2html.min.css";
+        String diff2htmlJs = "https://cdn.jsdelivr.net/npm/diff2html/bundles/js/diff2html-ui.min.js";
+
+        String template = "<!DOCTYPE html>\n" +
+                "<html lang=\"en-us\">\n" +
+                "  <head>\n" +
+                "    <meta charset=\"utf-8\" />\n" +
+                "    <link rel=\"stylesheet\" href=\"" + githubCss + "\" />\n" +
+                "     <link rel=\"stylesheet\" type=\"text/css\" href=\"" + diff2htmlCss + "\" />\n" +
+                "    <script type=\"text/javascript\" src=\"" + diff2htmlJs + "\"></script>\n" +
+                "  </head>\n" +
+                "  <script>\n" +
+                "    const diffString = `\n" +
+                "temp\n" +
+                "`;\n" +
+                "\n" +
+                "\n" +
+                "     document.addEventListener('DOMContentLoaded', function () {\n" +
+                "      var targetElement = document.getElementById('myDiffElement');\n" +
+                "      var configuration = {\n" +
+                "        drawFileList: true,\n" +
+                "        fileListToggle: true,\n" +
+                "        fileListStartVisible: true,\n" +
+                "        fileContentToggle: true,\n" +
+                "        matching: 'lines',\n" +
+                "        outputFormat: 'side-by-side',\n" +
+                "        synchronisedScroll: true,\n" +
+                "        highlight: true,\n" +
+                "        renderNothingWhenEmpty: true,\n" +
+                "      };\n" +
+                "      var diff2htmlUi = new Diff2HtmlUI(targetElement, diffString, configuration);\n" +
+                "      diff2htmlUi.draw();\n" +
+                "      diff2htmlUi.highlightCode();\n" +
+                "    });\n" +
+                "  </script>\n" +
+                "  <body>\n" +
+                "    <div id=\"myDiffElement\"></div>\n" +
+                "  </body>\n" +
+                "</html>";
+        template = template.replace("temp", builder.toString());
+        FileWriter fileWriter = null;
+        try {
+            fileWriter = new FileWriter(htmlPath);
+            BufferedWriter buf = new BufferedWriter(fileWriter);
+            buf.write(template);
+            buf.close();
+            fileWriter.close();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+}
+