The paper connects trajectory model with the man-machine interface of MFC, which can make the flight parameters and trajectory-drawing together in real-time, being the favorable interaction platform of trajectory design. Through the integrated platform users can obtain a series of flight parameters, such as flight time, velocity, location, impact angle and so on. So we can obtain the changing rule of parameters directly, which can be the basic elements for feasibility and optimization of the whole trajectory design. The platform has modular programming language, and every module has independent function, which can be called by other software independently. With standard structure definition, input/output interfaces meet the function of communication. And the platform has some interface for the secondary development.