The model of multibody system dynamics for the deployment process of space deployable mast is firstly established in this paper. The optimal control model is then developed by selecting thecontrol force as a variable. And the selection of the optimal control force results in the smooth and rapid deployment of the space mast. To avoid a large number of complex sensitivity calculation based on gradientbased optimization method in the process of finding optimal control force, genetic algorithm is used to search global optimization in this paper. Meanwhile, higherorder variational numerical integration method is employed to solve dynamics equation in the iterative optimization process, which leads to high stability. Finally, taking the scissor space deployable mast as an example, the genetic algorithm is utilized to control its deployment process optimally.