To improve the safety of the webbing subsystem of the survival parachute, the dynamic model of parachute-webbing-dummy system was developed, and the load of the center of mass of dummy was analyzed for the varied parameters of webbing and detachment lock. For the airdrop test of dummy in the high speed, the fifteen degree of freedom dynamic model for the parachute, detachment lock and dummy was developed by using the multi-body dynamic method. The webbing was modeled by semi-mass-damping model to join the parachute, detachment lock and dummy. The parachute opening force was calculated by using the load of test. The dynamic process of dummy and the webbing for the typical condition was simulated by using the proposed model, and the reasonableness of the model was verified. The effect of the load of the dummy mass center was analyzed for the position of detachment lock, the length of webbing, and the property of the webbing material. The results of the analysis can be used for the design of the webbing and the determination of the position of the detachment lock.