Based on the analysis of the characteristics of laser guidance semi-physical simulation system,combined with the working principle of laser strapdown seeker,a line-of-sight simulation algorithm in semi-physical simulation system based on synthetic line-of-sight is proposed.On the one hand,the synthetic line-of-sight simulation model is established based on the laser guidance semi-physical simulation system architecture,which is built on diffuse reflection screen and three-axis turntable,and the correction algorithm of synthetic line-of-sight simulation error is designed on the basis of analyzing the influence of installation error on synthetic line-of-sight simulation accuracy; on the other hand,the synthetic line-of-sight simulation model and error correction algorithm are simulated.The simulation result indicates that this algorithm is feasible in engineering application and is of great significance to improve the test and simulation capability for strapdown seeker of laser guidance semi-physical simulation system.