With the rapid development of power load management system，the requirement of network information security has been improved continuously. First, the data transmission character of load management system is analyzed.Then，by taking into account the demand for power load management system data transmission protocol，this paper presents a solution for data encryption and secret key management. It takes different algorithms to encrypt each layers of protocol according to every character of wireless communication mode. Finally, the encryption solution’s performance is analyzed. The result indicates that the solution has improved the information security performance effectively.