The separation process of submunitions under supersonic velocity is a typical multi-body separation problem including multi-body motion boundary and complex aerodynamic flow field interference.Based on the nested grid technique,the equations of convection physics and the equations of 6 degrees of freedom of rigid body dynamics are coupled,influence of the structure characteristics (such as number,missile wings,arrangement,etc.) of the submunition on the flow field characteristics in the separation process is emphatically studied.Results show that the method of overset grids can well simulate the complex aerodynamics flow condition of multiple missiles.Under certain circumstances,more bullets will bring stronger aerodynamic coupling effect in;Missile wings can greatly improve the static stability of bullets;Compared with “circular” distribution,“central circular” distribution tends to accelerate the separation of projectile bodies.