To achieve the trajectory scene quasi-real-time simulation, the trajectory model was created, and the missile 3D model and landform model were created using Multigen Creator software. The process and key technologies of the trajectory scene quasi-real-time simulation were analyzed based on Vega Prime. To achieve the quasi-real-time simulation, the high precision multi-media timer was used. The data cross-process exchange between trajectory simulation and scene simulation wais implemented using memory mapping file technology. The method's availability was verified by the trajectory scene quasi-real-time simulation program developed through using C + + to call Vega Prime API function in. NET frame. The designer can observe and analyze missile flight status through the trajectory scene simulation, and provide the reference for the trajectory analysis and design.