In order to ensure the security of data communication in the electricity consumption information collection system of power users, this paper proposes a security method for data exchange between the master station and the terminal data based on the key agreement mechanism. The method is mainly completed in three steps: first, the master station and the terminal A session channel is established between the two, and session key negotiation is performed to obtain the session key used in the subsequent data exchange process; then, the session key in the session key negotiation is used to perform the authentication operation of the master station to the terminal; finally, the terminal to the master station is used. station for authentication. At the same time, security policies such as encryption and signature are adopted in the process of data interaction. Through these three steps, the mutual authentication between the master station and the terminal is completed, a secure communication channel between the master station and the terminal is established, and the secure data exchange between the master station and the terminal is finally realized.