Aiming at the dynamic impact effect of airborne rocket during launching, the gas jet flow field of helicopter airborne rocket system in the whole launching process was calculated. Through the 3D unsteady numerical simulation method, combined with the dynamic grid method and the block hybrid grid model, the influence of the rocket nest structure on the impact effect under different missile loading conditions was compared. The results show that the maximum shock overpressure on the fuselage surface is about 10 kPa, the initial shock wave flow field development process is similar under different missile loading conditions, and the overpressure distribution is a single-peak function, but the shock flow field change is more complex when the rocket is launched from the tube under no-load condition, and the maximum overpressure distribution law of the fuselage is a double-peak curve.