Abstract: Route searching is the core module of the computer interlocking software. The search algorithm directly affects the efficiency of route searching. In this paper, the A * search algorithm was used to improve the efficiency of route searching, and C# compiler was used to build the interlocking simulation platform of urban rail transit to test the performance of the algorithm. On the simulation platform, the route processing process of urban rail transit interlocking system was simulated, and the station type data structure was constructed. The A * search algorithm was applied to the route search process, and the search was guided by the heuristic information to make the search more efficient and intelligent. Finally, the interlocking function of the simulation platform was improved, and the interaction between human and computer was accomplished.