Abstract: The energy-momentum method based on a modifying conventional Lagrange equation and the conservation of energy/momentum and angular momentum is applied for the deployment analysis of space membrane structures, and it achieves computation accuracy and the unconventionally stable time integration. During non-linear deformation analysis, a stiffness reduction model of membrane wrinkle and slack is introduced, and the thermodynamic property of gas, the interaction between gas and membrane, self-contact of the membrane and so on are taken into account. Results of a micro gravity experiment are presented for the deployment of an inflatable tube. The simulation results obtained from the proposed numerical method agree with the experimental results very well, the variation of pressure and volume according to the basic theory, which shows the proposed numerical method, is suitable for the deployment analysis of the space membrane structures. Finally, numerical analyses of some typical space membrane structures in the energy-momentum method are conducted. Compared to conventional finite element methods, the energy-momentum method provides much flexibility for solving deployment analyses of space membrane structures because of this method can guarantee the stabilization of time integral and iteration.