An economic and safety design proposal of the spatial grid structure is very difficult to find according to traditional design method.The group search optimization and its improved algorithm are applied in optimization design of a spatial grid structure in this paper. In this paper the finite element model of the spatial grid structure is firstly built through the platform of ANSYS. Then based on the parameterized programme language ADPL of ANSYS ,the group search optimization (GSO) and the quick group search optimization(QGSO ) are compiled ,the optimization analysis of the spatial grid structure are carried out. Finally, the optimization results and the optimization one from ANSYS are compared. It show that the optimization methods hereinbefore are feasible and the design proposals of them are better than the one of ANSYS.