The purpose of this paper is to study the type optimization of small satellite major joint, which is based on static and buckling analysis of honeycomb sandwich plates. Firstly the 3-D FEM model of honeycomb sandwich plates was established by the sandwich plate theory, in which the fork-form or faceplate major joint was buried beforehand. After the liner static and buckling analysis, the maximal Von-Mises stress and buckling load were obtained. Compared with the result of experiment, the failure causation to the Honeycomb Sandwich Plates was then determined. Finally the influence of the structural parameters upon load capacity was discussed, and the optimum major joint type was ascertained.