Abstract: Due to the advantages in automatic inspection, intelligent identification of equipment status and alarm functions, intelligent video surveillance system has become one of the key basic devices for the intelligent and IoT (Internet of Things) substation, which is very important for the significant improvement of the power supply reliability, and the economic benefits of the power grid. However, when subjected to transient electromagnetic harassment like lightning strikes, operating overvoltage or short circuit ground, intelligent video surveillance system is prone to offline, downtime and even damage, which seriously affects the real-time monitoring and status identification of the substation. The electromagnetic interference of intelligent video surveillance system caused by ground short circuit of high voltage equipment in substation is systematically studied, including the propagation rule, coupling path and interference characteristics of transient electromagnetic disturbance. Through the simulation calculation, the electromagnetic characteristics such as ground potential rise of the ground network under the ground short circuit fault are obtained, and the voltage distribution of the secondary cable shielding layer with different grounding modes, different distances from the ground fault point and different lengths, and the disturbance voltage of the cable port of the video surveillance equipment are analyzed. The results show that the disturbance voltage of 125 m double-ended shielded cable port can reach 1 410 V when the ground short-circuit fault occurs. The research results provide an important basis for transient electromagnetic disturbance evaluation and anti-interference design of video surveillance system in intelligent substation.