Matinez et al has proposed a secure RFID protocol which only relies on the use of Elliptic Curve Cryptography and a zero knowledge based authentication scheme. In this paper, we present that the proposed protocol can't resist desynchronization attack. The attacker only block the last acknowledge message from Back End Server. Then the share key of Tag and Back End Server is different. For this, we propose our revised scheme, and prove that revised scheme can resist desynchronization attack.