According to the theory of plate with consideration of shear deformation and three gen -eralized displacements,the orthogonal and ortho-laid space truss has been assumed as or-thotropic sandwich plate with three different materials in this paper.A basic function,andthe frequency equations and buckling equations of the space truss is given by dispersedGalerkin method of MWR. Numerical examples show that the method is simple and accura-cy.