In this paper, we proposed a new secure RFID(Radio Frequency IDentification) mutual authentication protocol on insecure communication channel which assumed that all communication channels between the database, the reader and the tag are insecure communication channels. The proposed protocol used a secure one-way hash function and the goal is to improve search time of a tag ID and overload of hash calculational load in DB. In addition, the proposed protocol supports not only basic security requirements to be provided by RFID mutual authentication protocol but also forward secrecy, and the tag does not generate a random number to reduce overload of processing capacity in it.