The fidelity of UAV simulation training system will directly affect the training effect of the operator. In order to improve the fidelity of the simulation training system for increasing the immersion and improving the training efficiency, taking the consistency of simulated flight and real flight as the design goal, this paper presents a new method to design high realistic UAV simulation training system based on airborne code. Combing the real UAV, the simulated flight and the real flight logic response are realized by using the host computer code technology. The practice results show that the system can improve the training effect, shorten the training time, and speed up the development of the UAV.