diff --git a/src/main/java/com/ansj/vec/Word2VEC.java b/src/main/java/com/ansj/vec/Word2VEC.java
index f942f01..2ccf09a 100644
--- a/src/main/java/com/ansj/vec/Word2VEC.java
+++ b/src/main/java/com/ansj/vec/Word2VEC.java
@@ -280,7 +280,7 @@ private float[] sum(float[] center, float[] fs) {
 		}
 
 		if (center == null) {
-			return fs;
+			return Arrays.copyOf(fs, fs.length);
 		}
 
 		for (int i = 0; i < fs.length; i++) {