In this paper,an accurate mathematical model of pedestal forces of a general space structure is established according to the Coulomb's law of friction and mechanical concepts. Two methods of solving, which are named the method of mathematical programming and spring restraint, are presented. Meanwhile, a simple way of structural analysis by finite element is pointed out considering the pedestal frictional forces of structure. Some examples are given. The numerical results show that the methods are very efficient. The research results have been applied to optimum structural design in a practical engineering.