In recent years, with the transformer substations basically unattended, a new topic for the security of power equipments and electric power lines is presented. Many alarm systems based on ac high-voltage grid, electronic pulse fence or infrared electronic fence have been installed in substations. In this paper, we propose an intelligent anti-theft alarm system based on laser fence and wireless communication network technology. Once occlusion of the laser beams occurs, it will transmit alarm information with accurate location to the control center through ZigBee network, and then send short messages to the defender's phone by GPRS. Moreover, the on site searchlights could be remotely controlled by SMS with GPRS network. The architecture and implementation of the system is described in detail. Practical results show that our system is high-security, low-power and low false-negative compared with the conventional anti-theft systems.