Abstract: Route searching is one of the core parts of computer interlocking and its efficiency and accuracy is vital to ensure the safety of traffic control. A directed graph model based on the structure of railway station yard is modeled and the problem of searching routes in a railway station yard is then converted as the problem of traversing a directed graph. According to the characteristics of simplified railway station yard graph, traditional Dijkstra algorithm is improved from the aspects of data storage and queue structure, breadth-first search is adopted, and a route searching strategy with the shortest path as objective function is proposed. Furthermore, a simulation program is built to verify this algorithm and the simulation results show that this improved Dijkstra algorithm can complete searching types of routes accurately and efficiently.