Abstract: Store separation is one of the essential issues for weapons in warfare missions, and matters to the carrier safety. In this paper, based on the CFD methods including polyhedral hybrid mesh, overset mesh and 6-DOF equations of rigid body motion, the simulation of store separation of a calibration model was carried out. The effect of initial ejection forces on the separation safety was studied, and the separation characteristics in both the longitudinal and lateral motions were analyzed, which can be used as a reference for engineering applications.