In order to make the quantum key agreement process immune to participant attacks, it is necessary to introduce the authentication in the communication process. A quantum key agreement protocol with identity authentication that exploits the measurement correlation of six-particle entangled states is proposed. In contrast to some recently proposed quantum key agreement protocols with authentication, this protocol requires neither a semi-trusted third party nor additional private keys in the authentication process. The entire process of authentication and key agreement can be achieved using only n six-particle entangled states, which saves communication costs and reduces the complexity of the authentication process. Finally, security analysis shows that this scheme is resistant to some important attacks.