Wireless transmission, broadcast of signals, resource-constraint disturb the reliability of Radio Frequency Identification (RFID) system and block the deployment progress of RFID techniques. Through the analysis of current common RFID authentication protocol, an authentication protocol based on Hash function and key array was proposed. The new protocol used one-way Hash function value instead of label identifier, and designed independent authentication key for each pair between the reader and the tag in the certification process. It could resist several possible attacks, including eavesdropping, location tracking, re-transmission attacks, Denial of Service (DoS), tampering and other attacks. It has obvious advantages in enhancing the tag identity privacy, and resisting the threat from within the system.