Abstract: In this paper, the CFD simulation of rocket aerodynamic characteristics considering the influence of bottom engine jet was carried out. The differences in flow field structure, surface pressure distribution and overall aerodynamic force and moment characteristics of the rocket at subsonic and supersonic speeds with or without jet flow were compared. The simulation results show that the jet flow has a significant influence on the axial force, normal force and pitching moment of the rocket at subsonic speed, and it can also reduce aerodynamic control moment of the tail rudder. The jet flow only affects the axial force when the rocket is at supersonic speed. The simulation results are consistent with the aerodynamic identification results of flight test. Based on the simulation results, a compromise aerodynamic characteristics design method considering the influence of engine jet can be established, which can be used as a reference for the fine aerodynamic design of rockets.