Abstract: Based on the validation of wind tunnel experiment, numerical simulation on single projectile and projectile with ribbons-parachute were explored. Polyhedral mesh was adopted and the supersonic flows were conducted using finite volume method and SST turbulence model. Effects of the distance from projectile base to ribbons-parachute on the system drag performance were obtained. The influence mechanism was studied based on flow field structure. The result shows that there is a critical distance which has significant influence on the system drag. The critical distance can be determined by the gradient of turbulence kinetic energy of in wake flow.