The purpose of the dummy high speed airdrop test is to evaluate the maximum overload on the human body during the process of opening the parachute. Due to the poor repeatability and high cost of the test, it is necessary to establish a calculation model to provide theoretical basis for the system design. Based on impulse theorem, the maximum dummy overload calculation model is established to calculate the maximum dummy overlord quickly under a certain airdrop condition. The typical high speed airdrop system is selected as the instance to conduct the system simulation based on multi-body dynamics. The key parameters of the calculation model are determined by simulation results, and the mathematical expressions of the maximum dummy overlord calculation model are given. The results show that the calculation model can quickly and effectively determine the maximum dummy overlord, evaluate the safety of the life-saving parachute system, and has high engineering application value.