Martínez et al.have proposed a secure RFID protocol recently which relies exclusively on the use of Elliptic Curve Cryptography(ECC)combined with a zero knowledge-based authentication scheme.In this paper,we show that this proposed protocol is not secure against the tracking attack.To make the attack successful,the adversary needs to execute three phases.Firstly,the attacker just eavesdrops on the messages exchanged between Reader and Tag.Secondly,the attacker impersonates the Reader to replay the message which is obtained from the first phase.Finally,the adversary acts as a man in the middle to tamper the messages exchanged between Reader and Tag.Then we propose an enhancement and prove that the revision is secure against the tracking attack while keeping other security properties. Martínez et al. Established a secure RFID protocol recently which relies exclusively on the use of Elliptic Curve Cryptography (ECC) combined with a zero knowledge-based authentication scheme. In this paper, we show that that proposed protocol is not secure against the tracking attack.To make the attack successful, the adversary needs to execute three phases. Firstly, the attacker just eavesdrops on the messages between between Reader and Tag. Secondarily, the attacker impersonates the Reader to replay the message which is obtained from the first phase. Finally, the adversary acts as a man in the middle to tamper the messages for between both Reader and Tag. Chen we propose an enhancement and prove that the revision is secure against the tracking attack while keeping other security properties.