diff --git a/src/main/java/com/hankcs/hanlp/seg/Segment.java b/src/main/java/com/hankcs/hanlp/seg/Segment.java
index a7d943dd9..2de317032 100644
--- a/src/main/java/com/hankcs/hanlp/seg/Segment.java
+++ b/src/main/java/com/hankcs/hanlp/seg/Segment.java
@@ -290,7 +290,7 @@ protected void mergeNumberQuantifier(List<Vertex> termList, WordNet wordNetAll,
     public List<Term> seg(String text)
     {
         char[] charArray = text.toCharArray();
-        if (config.threadNumber > 1)
+        if (config.threadNumber > 1 && charArray.length > 10000)    // 小文本多线程没意义，反而变慢了
         {
             List<String> sentenceList = SentencesUtil.toSentenceList(charArray);
             String[] sentenceArray = new String[sentenceList.size()];
@@ -575,7 +575,7 @@ public void run()
     }
 
     /**
-     * 开启多线程
+     * 开启多线程（默认4线程）
      * @param enable
      * @return
      */
diff --git a/src/test/java/com/hankcs/demo/DemoMultithreadingSegment.java b/src/test/java/com/hankcs/demo/DemoMultithreadingSegment.java
index 883041053..e155c7c09 100644
--- a/src/test/java/com/hankcs/demo/DemoMultithreadingSegment.java
+++ b/src/test/java/com/hankcs/demo/DemoMultithreadingSegment.java
@@ -36,17 +36,24 @@ public static void main(String[] args)
             sbBigText.append(text);
         }
         text = sbBigText.toString();
+        System.gc();
 
+        long start;
+        double costTime;
         // 测个速度
-        long start = System.currentTimeMillis();
+
+        segment.enableMultithreading(false);
+        start = System.currentTimeMillis();
         segment.seg(text);
-        double costTime = (System.currentTimeMillis() - start) / (double) 1000;
+        costTime = (System.currentTimeMillis() - start) / (double) 1000;
         System.out.printf("单线程分词速度：%.2f字每秒\n", text.length() / costTime);
+        System.gc();
 
         segment.enableMultithreading(true); // 或者 segment.enableMultithreading(4);
         start = System.currentTimeMillis();
         segment.seg(text);
         costTime = (System.currentTimeMillis() - start) / (double) 1000;
         System.out.printf("多线程分词速度：%.2f字每秒\n", text.length() / costTime);
+        System.gc();
     }
 }
diff --git a/src/test/java/com/hankcs/test/seg/TestSegment.java b/src/test/java/com/hankcs/test/seg/TestSegment.java
index 1acfeaf0e..dc2b9e88d 100644
--- a/src/test/java/com/hankcs/test/seg/TestSegment.java
+++ b/src/test/java/com/hankcs/test/seg/TestSegment.java
@@ -237,4 +237,11 @@ public void testMultiThreading() throws Exception
             assertEquals(term1.offset, term2.offset);
         }
     }
+
+    public void testTryToCrashSegment() throws Exception
+    {
+        String text = "尝试玩坏分词器";
+        Segment segment = new ViterbiSegment().enableMultithreading(100);
+        System.out.println(segment.seg(text));
+    }
 }