Abstract: Three-way plate-like space trusses are simplified as sandwich plate, and are analyzed by the nontraditional theory of plates with consideration of shear deformation and three generalized displacements. Static analysis and natural vibration analysis of three-way plate-like space trusses has been studied based upon the idea of split rigidity. The calculating formulas for internal forces, displacements, and fundamental frequency are presented. The validation by finite element method shows that as a simplified method, split rigidity method is very accurate, whose error is less than 5 percent in general. It can be used in the preliminary design of engineering structures so that the internal forces and displacements of the space truss and their distributions can be obtained rapidly. Furthermore, its formula is more simplified and compact compared with other method.