Abstract: With background of terminal guided weapon, at first, a scheme of hardware-in-the-loop simulation(HILS) was derived; and the principle of laser semi-active seeker was introduced in detail. Secondly, in the limited indoor environment, mathematical model of geometry between missile and target was established; subsequently the optical characteristics of the laser received by seeker were researched; the model of HILS in the terminal trajectory was designed for guidance and control system. In the end, seeker and gyro was introduced into the closed loop of simulation, simulations were repeated many times under two different conditions of the initial state. In conclusion, the results indicate that guidance and control system of the missile based on this seeker and gyro is achieved correctly and have the ability to hit the target precisely.