In the present paper, an accurate 3D finite element model is presented for bucking analysis of soft-core rectangular sandwich plates. The sandwich plate is composed of three layers: top and bottom skins and core layer. Finite element model of the problem has been constructed in the ANSYS 11.0 standard code area. The effect of geometrical parameters of the sandwich plate is studied. Comparison of the present results with those of plate theories confirms the accuracy of the proposed model. The overall buckling loads calculated by FE model are higher than that of the accurate results and the maximum discrepancy is less than 10 percent.