In this research, the beam-column joint having lateral beams and slab was considered. The specimens receive two direction loadings. For reporting the influence of two directional loadings, lateral beams and slab in analysis, Three-dimensional nonlinear FEM analysis was done. The examination was done for obtaining fundamental data regarding the influence of the lateral beams, slab and two direction Loadings (forty five degree directional loadings). In addition, the purpose of this examination is to research the earthquake-proof efficiency of the joint. The most of seismic design provisions for RC joints of high rise buildings in all Seismic Guidelines around the world are based on earlier experimental studies. Design Guidelines for Earthquake Resistant RC Buildings Based on Ultimate Strength Concept, suggests that a 3-D interior beamcolumn joint should be independently designed for two principal directions. However, it is necessary to establish a more rational performance evaluation design for joints under two directional seismic forces. This can be accomplished by analytical study of stress transfer mechanisms of joints. Beam-column joints in reinforced concrete buildings are generally subjected to forces in two orthogonal directions during an earthquake. The structural performance of the joints under such seismic forces has not been understood clearly and rationally in previous studies. The stress transfer mechanisms of these joints are a 3-D problem, and the joint is confined by its lateral reinforcement, transverse beams, a slab and column axial forces. It is necessary to understand the structural performance of joints subjected to two directional seismic forces, not only by experimental studies but also by using 3-D analytical techniques. In order to understand the damages of concrete in a joint, moreover, accumulated consumption energy of concrete elements in FEM analysis was calculated. It is very important to discuss the stress transfer mechanisms and the damages of concrete in a joint toward the establishing of a more rational performance evaluation design of RC structures.