In recent years, the public security department has insisted on technology to promote the high-quality development of public security work in the new era. It not only builds a three-dimensional patrol and defence system, but improve the level of patrol, defence and control management vigorously. At present, an intelligence-aided patrol system has been initially formed, and video patrols and law enforcement duty supervision have been carried out. However, the application of new technologies and the innovation of policing mechanisms in public security departments still have some problems. For example, unbalanced regional development, insufficient deepening of intelligent applications and insufficient systematization of applications, which greatly restrict the effectiveness of public security patrol and defence in practice. Based on this, our study identifies the crime hotspots in the city through EXCEL data analysis, and identifies them as patrol points. By applying the shortest route algorithm in the genetic algorithm, a precise patrol route is formed. Based on this, the precise patrol route is displayed on a map using a visualization tool and then fed back to the police terminal equipment. This project enables police patrols to be more accurate and patrol routes to be optimized. It improves the police patrol system and provides the basis for the construction of an intelligent patrol system.