For the problem in the mission design demands, the influence of the drag mode on the deployment property of the space net system was investigated. The dynamic model was set up and verified by ground test result. Evaluation criterion of space net system was set up to meet the mission demands and the impact that the drag mode brought in was studied through a finite element method. The simulation models, in which mass of the net and initial projection energy were kept the same, were built based on the finite segment approach for four and six points drag modes. Simulation result of the evaluation criterion indicates that the system flight performance indexes and the dynamic evaluation criterions are improved in the six points drag mode, the energy utilization rate and system reliability, however, show minor decrease.