diff --git a/test/core/test_preprocess.py b/test/core/test_preprocess.py
new file mode 100644
index 00000000..bff33ed3
--- /dev/null
+++ b/test/core/test_preprocess.py
@@ -0,0 +1,43 @@
+import os
+import unittest
+
+from fastNLP.core.preprocess import SeqLabelPreprocess
+
+
+class TestSeqLabelPreprocess(unittest.TestCase):
+    def test_case_1(self):
+        data = [
+            [['Tom', 'and', 'Jerry', '.'], ['n', '&', 'n', '.']],
+            [['Hello', 'world', '!'], ['a', 'n', '.']],
+            [['Tom', 'and', 'Jerry', '.'], ['n', '&', 'n', '.']],
+            [['Hello', 'world', '!'], ['a', 'n', '.']],
+            [['Tom', 'and', 'Jerry', '.'], ['n', '&', 'n', '.']],
+            [['Hello', 'world', '!'], ['a', 'n', '.']],
+            [['Tom', 'and', 'Jerry', '.'], ['n', '&', 'n', '.']],
+            [['Hello', 'world', '!'], ['a', 'n', '.']],
+            [['Tom', 'and', 'Jerry', '.'], ['n', '&', 'n', '.']],
+            [['Hello', 'world', '!'], ['a', 'n', '.']],
+        ]
+
+        if os.path.exists("./save"):
+            for root, dirs, files in os.walk("./save", topdown=False):
+                for name in files:
+                    os.remove(os.path.join(root, name))
+                for name in dirs:
+                    os.rmdir(os.path.join(root, name))
+        result = SeqLabelPreprocess().run(train_dev_data=data, train_dev_split=0.4,
+                                          pickle_path="./save")
+        result = SeqLabelPreprocess().run(train_dev_data=data, train_dev_split=0.4,
+                                          pickle_path="./save")
+        if os.path.exists("./save"):
+            for root, dirs, files in os.walk("./save", topdown=False):
+                for name in files:
+                    os.remove(os.path.join(root, name))
+                for name in dirs:
+                    os.rmdir(os.path.join(root, name))
+        result = SeqLabelPreprocess().run(test_data=data, train_dev_data=data,
+                                                           pickle_path="./save", train_dev_split=0.4,
+                                                           cross_val=True)
+        result = SeqLabelPreprocess().run(test_data=data, train_dev_data=data,
+                                          pickle_path="./save", train_dev_split=0.4,
+                                          cross_val=True)