diff --git a/README.md b/README.md
index aa75cc0d27..f598c21e8f 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,8 @@
 Pika
 ====
 
-Pika is redis like database.
+Pika is a database that has the same feature as redis. The reason why we develop
+Pika is to solve redis's memory limitation
 
 Pika used Nemo as storage engine, Nemo is developed base on rocksdb.