Abstract: With the advancement of sensing technology and the miniaturization of sensors, the Internet of Things (IoT) technology has been rapidly developed in the power system. Due to the large number, extensive interconnection, and decentralized distribution of the power distribution IoT terminals, they have jumped out of the scope of border security protection, which has caused the terminals to become the main target and springboard for attacking the power grid. Firstly, combined with the power IoT architecture, the terminal security challenges are summarized from the aspects of software, hardware, communication, etc., the terminal risk characteristics are further summarized, and the protection mechanism deployed to deal with the terminal risk is analyzed and its shortcomings are presented. Then, according to the existing protection vulnerabilities, the terminal security issues are analyzed, the encryption and authentication issues, data privacy security, time synchronization attack, malicious base station attack are focused on, and the communication block attack of 230 MHz power IoT terminal and their corresponding protection research are reviewed. Finally, the applications of new generation AI technologies such as deep learning in the security of IoT terminals are reviewed and prospected.