In recent years, the video surveillance system data of various facilities, places and key parts in the power industry has been widely used, and a large number of hidden dangers of security vulnerabilities and data leakage have occurred. The use of video surveillance systems to obtain important asset information in key places is worrying. Therefore, this paper proposes a research based on the improved Tent chaotic map in the encryption of video surveillance data in substations. This paper constructs an improved Tent map, and compares the t classical tent chaotic map, the classic Logtisic chaotic map, and the improved Tent chaotic map. In terms of performance in bifurcation graph, correlation dimension value, etc., experimental research shows that this improved chaotic map has improved mapping range, randomness, uniformity, etc. compared with the classical Tent map. Based on this chaotic map, the permutation group strategy is used to obtain the ciphertext image, which realizes the encryption of the video surveillance data of the substation.