Abstract: The 3D interlocking simulation software of outdoor scene for railway station yard implemented the threedimensional real-time dynamic replay of the station interlocking control process. This software was designed by using 3D MAX software to model each signal device, and using C# programming language, the animation of turnout conversion driven by switch machine, light band display of track circuit and lighting of signal machine was made on Unity3D platform. By receiving real-time data from computer interlocking simulation software to drive the outdoor 3D equipment action of station yard, the simulation results of outdoor operation and several kinds of faults of station such as alignment route, analog walking and so on were displayed intuitively, which served the teaching or training of station interlocking control system.