ABSTRACT: In this paper, we develop a parametric model method and simulate the deployment mechanism of inflatable antenna structures. Different folded methods are developed for the primary members of inflatable antenna structures, which include inflatable tubes, an inflatable torus, a reflector etc. The unstressed configuration and the folded configuration of these members are modeled parametrically using the developed folded methods. A simulation software is developed for the deployment mechanism of inflatable structures by the improved spring-mass system. The driving forces in the deployment process, i.e. the gas pressure and the moment of the fold hinges, are analyzed for each member. During the development process, self-contact or collision with the membrane occurs. A rule for identifying self-contact elements is applied, and a penalty function method is developed to solve this challenging problem. Finally, the equation of motion is solved using finite difference method. The developed simulation software is validated by simulating a cylindrical inflatable tube that is folded in half, and the simulation agrees well with the experiment. The deployment mechanism of the antenna model similar to that for the Inflatable Antenna Experiment (IAE) is modeled, analyzed and estimated. The deployed configurations and the dynamic parameters of each node are obtained. The numerical simulation results show that the simulation software for the deployment mechanism can correctly predict the deployment process of inflatable antenna structures.