The hanging type air launch vehicle has complex flight experience of sonic, transonic, supersonic and low, high attack angle from separation of rocket and carrier to first stage separation of rocket. Therefore, the aerodynamics investigation in different flight conditions is the foundation of a successful launch. The three-dimensional model of rocket was designed and built according to the features of hanging type air launch vehicle. Based on the flight state of rocket, the separation process was divided into unpowered flight stage, transonic into supersonic flight stage and accelerated flight stage. The aerodynamic characteristics of rocket were studied in different flight conditions of mach and angle of attack by using CFD. To study the influence of fuselage length and horizontal tail anhedral on aerodynamic characteristics, fuselage length and horizontal tail anhedral were increased by +0.5 m, +1.0 m, +1.5 m, +2.0 m and -5°, -10°, -15°, -20°, -25°. The simulation results show that the different fuselage length and the wing generate different aerodynamic interference, which would influence the lift resistance of the rocket; while the horizontal tail anhedral has no influence on rocket lift resistance characteristic, moreover, the pitching stability of the improved rocket model has been enhanced.