In orde r to reduce computational cost during satellite bus structure optimization and s atisfy the global convergence, the radial basis function is applied to dealling with structure optimization. As the truss structure optimization involves size, t opology and geometry variables, continuous relaxation is used to trea t discrete variables. Furthermore, the Lagrangian multiple method is applied to converting a constrained optimization problem to an equivalent unconstrained opt imi zation problem with bound constraint. Then the radial basis function is used to approximate the Lagrangian function, and the optimum is obtained through using g lobal optimization strategy for the approximated model. During the satellite bus structure optimization process, the parameter of Lagrange function and radial b asis are updated until the process searches a feasible optimum. Finally, the propo sed strategy is applied to a practical satellite bus truss structure, thus demon strating the high efficiency.