For the research of a certain unmanned aerial vehicle's inertial navigation system and flight control system, a simulation system of the three-axis turntable is designed. This system adopts host computer and turntable control computer. S-Function with C++ language is used in the host computer to establish the serial communication interface model. Fast data communication between the two computers is achieved by the RS-422 serial port. The test shows that the system has the characteristics of high precision, real-time and reliable operation. This system can be extended to hardware-in-the-loop simulation experiment.