Radio Frequency Identity (RFID) has become more popular day after day in supply chain. However, because of its contact-less retrieval and substantial commercial interests in the supply chain, attackers would seek market intelligence or privacy over RFID. In order to protect commercial benefits, how to ensure the security of RFID system is extremely important. In this paper, based on Liu’s et al. and Yu-Hung Peng’s schemes, we propose a more secure RFID authentication scheme. Proposed scheme add into the reader-to-tag authentication, which eliminate the possibility of hostile reader attack. Furthermore, by equipping hash lock method with random number, our scheme also supports untraceability. Security analysis indicates that the proposed scheme has the highest security.