This paper is focusing on the model to predict the ultimate shear strength on joints of composite system (RCS) with reinforced concrete columns and steel beams considering the transverse beam. It reviews the ratio of experimental shear strength to design strength calculated by existing desist equations which are proposed by Kanno, Wight, Noguchi and the rising of strength by the transverse beams. When the shear strength of joints is estimated, it is necessary to do research work for the stress transfer mechanism considering two concrete strut of inner and outer panel by web of the transverse beam. In order to confirm it requires further experimental and analytical study.