In this study, moment curvature the relation of T cross-section reinforced concrete beams with high tensile reinforcement ratio was investigated. The parametric study was performed for T cross-section reinforced concrete beams by taking the tensile reinforcement ratios as high and constant and changing the concrete grade and compression reinforcement ratios. Six types total 66 different T cross-section reinforced concrete beams having different parameters were designed. Moment-curvature relations of T cross section reinforced concrete beams were obtained by considering the nonlinear behaviors of beam materials. Moment-curvature values,curvature ductility values, ductility ratios and effective stiffness values were calculated for the case of yield and failure stages. The results obtained from different parameters from the analysis results are presented in tables and the results were evaluated. The behavior of T cross-section reinforced concrete beams has been interpreted using the values of curvature ductility, effective ductility ratio, effective rigidity, yield and maximum moment capacities of beams. As the compression reinforcement ratio of T cross-section reinforced concrete beams increase, yield moment and maximum moment bearing capacity values increase, but the yield curvature values decrease. Maximum curvature values of the T cross-section beam without compression reinforcement (ρ '= 0) were obtained lower than the beams with compression reinforcements. For the T cross-section beams with compression reinforcement between ρ '= 0.1ρ and ρ'=ρ, the maximum curvature values are stayed constant. It has been observed that the compression reinforcement has a positive effect on the curvature ductility, effective rigidity, maximum curvature, yield moment and maximum moment bearing capacity of the reinforced concrete beams with T section.