Abstract: In order to solve the problems of remote supervision of high-risk scene in power system and unattended field, this paper analyzes the technology of fiber disturbance signal recognition, fast intrusion detection algorithm and location of interference based on fiber interference principle, combined with the key technologies of video monitoring, sound and light alarm system, an intelligent early warning system architecture of perimeter security based on fiber-optic Sagnac interferometer is proposed. The system has stable performance, high sensitivity, timely response and other important characteristics, effectively solve the traditional early warning system of poor anti-interference ability, high false alarm rate, etc. The utility model can realize all-weather and non-intermittent intelligent centralized management and control of power system perimeter, and realize the functions of system intrusion, automatic identification and identification of security accident signals, remote automatic alarm, intrusion behavior intimidation, etc.In this paper, an intelligent early warning system for security protection in perimeter has been constructed, which enriches the application of fiber-optic Sagnac interferometer in Intelligent Early Warning System.