The disturbances occurred during missile launching makes trajectory deviate from expectation, it is necessary to investigate the influence of disturbances on the trajectory parameters. The influence of several typical disturbances on some missile's trajectory parameters were compared through simulation, the six degree-of-freedom model of standard trajectory was established, and then models with four typical disturbances (eccentricity of motor thrust, wind interference, initial disturbance, separating disturbance) were found. Simulation tests for four ultimate situations were carried through, and the influence of each factor on missile trajectory parameters was analyzed. The results show that for this missile's flight characteristics, the influence of frequent interference is much larger than that of the instantaneous interference, the position is influenced mainly by the thrust eccentricity, the attitude angle is mainly affected by wind disturbance, and the instantaneous interferences just have little effect on ballistic parameters before and after the action time.