diff --git a/src/main/java/proteomics/Validation/CalFDR.java b/src/main/java/proteomics/Validation/CalFDR.java
index 819931b..ae18a89 100644
--- a/src/main/java/proteomics/Validation/CalFDR.java
+++ b/src/main/java/proteomics/Validation/CalFDR.java
@@ -48,6 +48,9 @@ public static Map<String, Entry> calFDR(String sqlPath, boolean cal_evalue, Stri
         sqlConnection.close();
 
         final int array_length = 1 + (int) Math.ceil((max_score - min_score) * inversePrecision);
+        if (array_length <= 0) { // there is no hit
+            return scanIdEntryMap;
+        }
         double[] decoy_count_vector = new double[array_length];
         double[] target_count_vector = new double[array_length];
         double[] fuse_count_vector = new double[array_length];