It is very important to solve the security access problem of the LTE power network in the face of the wireless access of the mass monitoring terminal of the transmission line. In order to improve the security and authentication efficiency of the power terminal accessing the LTE private network.. In this paper, the security enhancement evolved packet system authentication and key agreement mechanism (SE-EPS AKA) based on public key system is proposed. It introduces the public key Infrastructure(PKI) of the transport layer security (TLS) protocol, using the asymmetric encryption algorithm to generate a dynamic transmission key; at the same time, establish MAC address history access state table and priority access mechanism. The safety and time-time analysis of the proposed method was carried out, Experiments show that the proposed scheme improves the security and authentication efficiency of terminal access and has good practicality.