Owing to the excitation of circumstances of road surface or sea wave,when shooting the target,the tank and armoured car marching forward or the naval ships and boats will be vibrated randomly.And so the random changes for the speed of shell or bullet in gun muzzle will be engendered that the percentage of hits is affected. Under the hypothese that the model of system for a body in motion is linear and the speed of vertical vibration is very small,the shooting deviation and a few analysis methods for improving shooting percentage of hits are discussed in this paper.