Taking the Hardware-in-the-loop (HWIL) simulation of laser guided weapons as the background, we studied the laser target simulator in the paper, a suit of high precision and real-time laser target simulator was designed. The composition and design of the laser were discussed, focusing on the system of energy attenuator and controllable telescope. Experimental results show the laser simulator can simulate the energy and size of laser facular, and meet the need of HWIL of laser guided weapons.