Failure analysis of reinforced concrete deep beams is presented using the general purpose finite element system DIANA, with attention towards size effect and effects of bending span to depth ratio on shear behavior. Effects of shape and size of finite elements and boundary conditions on the failure of the beams are also investigated. It is shown that the maximum shear strength and failure process of the deep beams can be well simulated by the present analysis method. It has been proved that the element shape can influence on the prepeak shear response and tensile modeling alone, which takes into account fracture energy, is not sufficient to simulate the size effect of shear strength in reinforced concrete deep beams. Furthermore, the bending span to depth ratio has a significant influence on the shear strength, same as the shear span to depth ratio.