Abstract: Previous investigations have shown that an active jet vortex generator can control the flow separation of a supersonic boundary layer effectively, and can be adjusted according to actual situation. In this paper, the jets were mounted at the projectile shoulder of an original standard 122 finned projectile to investigate the flow separation control on the aerodynamic characteristics of the projectile. Numerical simulations were performed with the use of DES method to investigate the supersonic flow fields with and without jets, and the modifications of the boundary layer structures and aerodynamic data for two cases have been compared and discussed. Numerical results show that the jets control can inhibit fluid separation on the surface of a projectile, increase the lift and pitching moment, and reduce the oscillation of projectile body, as a result of improving the flight stability and firing accuracy, which can provide guidance for the improvement of supersonic projectiles.