diff --git a/NEWS.md b/NEWS.md
index 86316d90..a0cbbe07 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -28,6 +28,7 @@ Red Panda C++ Version 2.26
   - fix: Crash if include a non-exist header file in the source.
   - fix: Line numbers for problem case input/output/expected texteditors are not vertically centered.
   - enhancement: E-ink color scheme.
+  - fix: Use the system default encoding for input when running problem cases.
 
 Red Panda C++ Version 2.25
 
diff --git a/RedPandaIDE/compiler/ojproblemcasesrunner.cpp b/RedPandaIDE/compiler/ojproblemcasesrunner.cpp
index 67b11a7c..3dc7c58e 100644
--- a/RedPandaIDE/compiler/ojproblemcasesrunner.cpp
+++ b/RedPandaIDE/compiler/ojproblemcasesrunner.cpp
@@ -107,7 +107,7 @@ void OJProblemCasesRunner::runCase(int index,POJProblemCase problemCase)
         if (fileExists(problemCase->inputFileName))
             process.write(readFileToByteArray(problemCase->inputFileName));
         else
-            process.write(problemCase->input.toUtf8());
+            process.write(problemCase->input.toLocal8Bit());
         process.waitForFinished(0);
     }