Abstract: Firstly, in order to make optical axis of laser semi-active seeker track target fast, precession was divided into linear zone, transition zone and nonlinear zone based on error angle between optical axis and line of sight(LOS). Under some constraint conditions, in response to the problem that precession rate of the seeker was discontinuous, precession scheme of seeker's tracking loop was designed with Hermite Method. Secondly, a hardware-in-the-loop simulation(HILS) system of laser guided weapon was introduced, and model of geometry was founded in indoor environment. Finally, the locked seeker was fixed on Five-Axis Turntable, which was used to simulate the precession of seeker and attitude movement of missile. In two initial conditions of handoff, the results of trajectory HILS prove that the designed scheme of seeker's tracking loop is feasible for terminal guided weapon, and is able to hit the target precisely.