Increasing of building constructions demand affects the innovation for developing structural elements, especially in the beam element known as deep beams. The deep beam is a popular beam with an adequate ratio of a/d< 1.0. Therefore, Compared to the standard beam, The strength of the deep beam shows better. It also can be applied to various construction. Based on observations in the field, the length of the cross-section of the deep beam varies significantly, starting from the prismatic and non-prismatic shapes. Therefore, this research has conducted to determine the effect of non prismatic longitudinal section variations on the RC deep beam behavior using finite element method. The simulation model analyzed consists of one prismatic longitudinal section and two types of the non-prismatic longitudinal section. The result shows that the non-prismatic longitudinal of the deep beam gives effects on slightly decreasing flexural load, ductility and failure mode. The failure modes shown in models show the same characteristics, which are both experiencing shear failure.