Heavy cargo airdrop is a technique for rapid delivery of equipment to a designated ground area. It possesses the characteristics of rapid response and long-range operations. Heavy cargo airdrop systems are typically multibody systems. In this paper, the Newton-Euler method is used with reference to previous work. This method has been analyzed the forces on each rigid body in the system, so the physical meaning is clear. And it is expressed the complete force relationship of the system. The models with a small number of rigid bodies have a small computational effort in this paper. In this paper, the Newton-Euler method is used to numerically simulate the single parachute system model and the parachute swarm system model under a variety of working conditions. This paper analyzes the effects of different wind speeds, the projected area of the parachute, sling length, and the stiffness on the steady descent phase of the system. The differences are derived in characteristics of different systems under a variety of external factor.