diff --git a/src/main/java/org/jcnc/jnotepad/tool/EncodingDetector.java b/src/main/java/org/jcnc/jnotepad/tool/EncodingDetector.java
index dc0fac6..b601e40 100644
--- a/src/main/java/org/jcnc/jnotepad/tool/EncodingDetector.java
+++ b/src/main/java/org/jcnc/jnotepad/tool/EncodingDetector.java
@@ -23,6 +23,10 @@ import static org.jcnc.jnotepad.constants.TextConstants.UNKNOWN;
 public class EncodingDetector {
 
     private static final Logger LOG = LogUtil.getLogger(EncodingDetector.class);
+    /**
+     * 编码侦测概率，阈值：50%
+     */
+    public static final int THRESHOLD_CONFIDENCE = 50;
 
 
     private EncodingDetector() {
@@ -39,10 +43,20 @@ public class EncodingDetector {
         try (BufferedInputStream inputStream = new BufferedInputStream(new FileInputStream(file.getPath()))) {
             charsetDetector.setText(inputStream);
             CharsetMatch[] matchList = charsetDetector.detectAll();
-            for (CharsetMatch match : matchList) {
+            if (matchList == null || matchList.length == 0) {
+                return UNKNOWN;
+            }
+            CharsetMatch maxConfidence = matchList[0];
+            if (maxConfidence.getConfidence() < THRESHOLD_CONFIDENCE) {
+                return UNKNOWN;
+            }
+            for (int i = 1; i < matchList.length; i++) {
+                CharsetMatch match = matchList[i];
                 LOG.debug("{} : {}", match.getName(), match.getConfidence());
-                if (match.getConfidence() > 50) {
-                    return match.getName();
+                if (match.getConfidence() >= THRESHOLD_CONFIDENCE && match.getConfidence() >= maxConfidence.getConfidence()) {
+                    maxConfidence = match;
+                } else {
+                    return maxConfidence.getName();
                 }
             }
         } catch (Exception e) {