diff --git a/NEWS.md b/NEWS.md
index 946d9df6..a40760f2 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -16,7 +16,8 @@ Red Panda C++ Version 0.13.3
   - fix: Undo in the editor will lose line indents when no highlighter is assigned (the editing file is a not c/cpp source file);
   - enhancement: highlighter for GLSL (OpenGL Shading Language)
   - add a new template for raylib shader apps
-
+  - fix: project files' charset settings doesn't work correctly
+  
 Red Panda C++ Version 0.13.2
   - fix: "delete and exit" button in the environtment / folder option page doesn't work correctly 
   - fix: crash when closing the options dialog under Ubuntu 20.04 LTS ( no memory leak now)
diff --git a/RedPandaIDE/editor.cpp b/RedPandaIDE/editor.cpp
index 739755f9..d3d3fef9 100644
--- a/RedPandaIDE/editor.cpp
+++ b/RedPandaIDE/editor.cpp
@@ -394,6 +394,8 @@ const QByteArray& Editor::encodingOption() const noexcept{
     return mEncodingOption;
 }
 void Editor::setEncodingOption(const QByteArray& encoding) noexcept{
+    if (mEncodingOption == encoding)
+        return;
     mEncodingOption = encoding;
     if (!isNew())
         loadFile();
diff --git a/RedPandaIDE/mainwindow.cpp b/RedPandaIDE/mainwindow.cpp
index a3141131..535bf76c 100644
--- a/RedPandaIDE/mainwindow.cpp
+++ b/RedPandaIDE/mainwindow.cpp
@@ -980,7 +980,8 @@ void MainWindow::openFile(const QString &filename, QTabWidget* page)
             unit = mProject->findUnitByFilename(filename);
         }
         bool inProject = (mProject && unit);
-        editor = mEditorList->newEditor(filename,ENCODING_AUTO_DETECT,
+        QByteArray encoding = unit ? unit->encoding() : ENCODING_AUTO_DETECT;
+        editor = mEditorList->newEditor(filename,encoding,
                                     inProject, false, page);
         if (mProject) {
             mProject->associateEditorToUnit(editor,unit);
@@ -2011,7 +2012,8 @@ void MainWindow::loadLastOpens()
             unit = mProject->findUnitByFilename(editorFilename);
         }
         bool inProject = (mProject && unit);
-        Editor * editor = mEditorList->newEditor(editorFilename,ENCODING_AUTO_DETECT,inProject,false,page);
+        QByteArray encoding = unit ? unit->encoding() : ENCODING_AUTO_DETECT;
+        Editor * editor = mEditorList->newEditor(editorFilename, encoding, inProject,false,page);
         if (mProject) {
             mProject->associateEditorToUnit(editor,unit);
         }
diff --git a/RedPandaIDE/project.cpp b/RedPandaIDE/project.cpp
index a2d812e3..bb402939 100644
--- a/RedPandaIDE/project.cpp
+++ b/RedPandaIDE/project.cpp
@@ -1760,7 +1760,12 @@ const QByteArray &ProjectUnit::encoding() const
 
 void ProjectUnit::setEncoding(const QByteArray &newEncoding)
 {
-    mEncoding = newEncoding;
+    if (mEncoding != newEncoding) {
+        if (mEditor) {
+            mEditor->setEncodingOption(newEncoding);
+        }
+        mEncoding = newEncoding;
+    }
 }
 
 bool ProjectUnit::modified() const