With the increasing threat of space debris to spacecrafts and astronauts, the space debris clearance technology using flynet has become a research hotspot. In this paper, the space belt net with higher strength and less entanglement is used to replace the traditional flying net. Based on the spring particle method, MATLAB was used to simulate the ejection expansion process. In order to simulate the launching process of belt net better, this paper puts forward the evaluation index of the capture effect of space belt net. The influence of spring elasticity coefficient and spring elasticity coefficient on the unwinding process is discussed. Secondly, the launch parameters are analyzed, and the influences of launch velocity, launch Angle and mass block mass on the launch process are discussed. The results show that the larger elastic coefficient is beneficial to the belt network development process, and it is not suitable to select the large launching velocity, launching Angle and mass.