Reinforced concrete members form the main structure of a structure. The risk of corrosion of rebar is considered as an effective factor in determining the life of these structures, so identifying and investigating its destructive factors is very important, especially corrosion of longitudinal rebar; Because the weakness of concrete in tensile increases the possibility of cracking of tensile concrete and the formation of a bed to start the corrosion process in longitudinal rebar. The beginning of the corrosion process leads to a decrease in the cross-sectional area of the rebar and an increase in the corrosion products; This increase in volume due to the products causes tension around the rebar, which ultimately creates cracks in the concrete, reduces the adhesion between the concrete and the rebar, exfoliates the concrete surface and reduces the compressive strength of the concrete. Due to the fact that the adverse effects of rebar corrosion have been less studied in deep reinforced concrete beams, in this study, the corrosion effect of longitudinal rebar by applying elements such as: reduced cross section, reduced rebar yield strength, reduced concrete compressive strength, reduced adhesion The connection between concrete and rebar in ABAQUS finite element software on the stiffness and strength of deep reinforced concrete beams has been investigated. The results show that with the increasing percentage of corrosion of longitudinal rebar, the strength and stiffness of deep beams are significantly reduced so that when the longitudinal rebar reach 50% corrosion, it loses 51.38% of its strength and A reduction of 43.57% is difficult. Beam behavior has also changed from shear to bending due to corrosion and the stress-strain diagram shows the decrease in stress and strain with increasing corrosion percentage.