The precision of line of sight reproduction is a key factor of precision evaluation in Hardware-in-The-Loop(HWIL) simulation system for laser guided weapon. Base on the analysis on static and dynamic errors of line of sight in total, the movetion model with definite physics signification was set up by adopting multi-body system theories. After that, the model was verified by using the measure data of angle of sight in various motion including sine, exponent and typical scenario. The verification shows that the simulation results meet well with the measurement results as the error is less than 2.68′ and average error is less than 0.3′, and the model can describe the variation rules of angle of sight.