The work aims to build a virtual prototype model of pusher for packaging machine based on ADAMS. The simulation of pusher was carried out, based on which the hinge gap model, the flexible body model and the hinge gap flexible body model were established. Through the comparison with the motion curves of ideal model, the influences of each hinge gap and linkage flexibility on the kinematics law were analyzed. The effect of kinematic pair clearance (0.25 cm) on speed and acceleration of pushing plate was obvious, which caused oscillation; meanwhile, kinematic pair clearance (0.25 cm) and component flexibility were considered. The speed and acceleration curves obtained tended to be stable, which eased the hinge gap impact. Appropriate considerations taken for linkage flexibility can ease the oscillation generated by hinge gap, so as to enable the pushing plate to move stably.