To study the influence of thrust misalignment on trajectory of precision guided rocket, the thrust misalignment was geometrically analyzed, and the math model was built. The shooting test was done by Monte Carlo. Three results of powered course dispersion were obtained by changing angle of fire under the effect of thrust misalignment, and it is proved that angle of fire has bad effect on distance dispersion. The dispersion of powered course was simulated under the effect of gas misalignment and geometry misalignment, and the result proves thrust misalignment has bad effect on direction dispersion. The dispersion of final trajectory was obtained, and the result proves that dispersion scope is larger than the capture territory.