diff --git a/backend/src/main/java/io/dataease/service/chart/util/ChartDataBuild.java b/backend/src/main/java/io/dataease/service/chart/util/ChartDataBuild.java
index a0b32b407c..2e50a71a12 100644
--- a/backend/src/main/java/io/dataease/service/chart/util/ChartDataBuild.java
+++ b/backend/src/main/java/io/dataease/service/chart/util/ChartDataBuild.java
@@ -1012,7 +1012,7 @@ public class ChartDataBuild {
             switch (columnPermissionItem.getDesensitizationRule().getCustomBuiltInRule()) {
                 case RetainBeforeMAndAfterN:
                     if (StringUtils.isEmpty(originStr) || originStr.length() < columnPermissionItem.getDesensitizationRule().getM() + columnPermissionItem.getDesensitizationRule().getN() + 1) {
-                        desensitizationStr = String.join("", Collections.nCopies(columnPermissionItem.getDesensitizationRule().getM(), "X")) + "***" + Collections.nCopies(columnPermissionItem.getDesensitizationRule().getN(), "X");
+                        desensitizationStr = String.join("", Collections.nCopies(columnPermissionItem.getDesensitizationRule().getM(), "X")) + "***" + String.join("", Collections.nCopies(columnPermissionItem.getDesensitizationRule().getN(), "X"));
                     } else {
                         desensitizationStr = StringUtils.substring(originStr, 0, columnPermissionItem.getDesensitizationRule().getM() - 1) + "***" + StringUtils.substring(originStr, originStr.length() - columnPermissionItem.getDesensitizationRule().getN(), originStr.length() - 1);
                     }
@@ -1030,7 +1030,7 @@ public class ChartDataBuild {
                         desensitizationStr = "***" + StringUtils.substring(originStr, columnPermissionItem.getDesensitizationRule().getM() - 1, columnPermissionItem.getDesensitizationRule().getN()) + "***";
                         break;
                     }
-                    if (originStr.length() >= columnPermissionItem.getDesensitizationRule().getN() && originStr.length() < columnPermissionItem.getDesensitizationRule().getN()) {
+                    if (originStr.length() >= columnPermissionItem.getDesensitizationRule().getM() && originStr.length() < columnPermissionItem.getDesensitizationRule().getN()) {
                         desensitizationStr = "***" + StringUtils.substring(originStr, columnPermissionItem.getDesensitizationRule().getM() - 1, originStr.length());
                     }
                     break;