diff --git a/jvm-packages/xgboost4j-spark/src/main/scala/ml/dmlc/xgboost4j/scala/spark/XGBoost.scala b/jvm-packages/xgboost4j-spark/src/main/scala/ml/dmlc/xgboost4j/scala/spark/XGBoost.scala
index bd49e108c..78e844283 100644
--- a/jvm-packages/xgboost4j-spark/src/main/scala/ml/dmlc/xgboost4j/scala/spark/XGBoost.scala
+++ b/jvm-packages/xgboost4j-spark/src/main/scala/ml/dmlc/xgboost4j/scala/spark/XGBoost.scala
@@ -188,9 +188,9 @@ object XGBoost extends Serializable {
     implicit val sc = trainingData.sparkContext
     var overridedConfMap = configMap
     if (overridedConfMap.contains("nthread")) {
-      val nThread = overridedConfMap("nthread")
-      val coresPerTask = sc.getConf.get("spark.task.cpus", "1")
-      require(nThread.toString <= coresPerTask,
+      val nThread = overridedConfMap("nthread").toString.toInt
+      val coresPerTask = sc.getConf.get("spark.task.cpus", "1").toInt
+      require(nThread <= coresPerTask,
         s"the nthread configuration ($nThread) must be no larger than " +
           s"spark.task.cpus ($coresPerTask)")
     } else {