Abstract: In order to investigate the effect of constitutive behaviors on mechanical performance of members and structures, the constitutive relationship tests of LYP100 low yield point steel were carried out firstly. The monotonic behavior, ductility, hysteretic behavior, energy-dissipation capacity and cyclic constitutive model were analyzed. Based on these results, the constitutive relationship of low yield point steel, normal strength steel (Q345B) and high strength steel (Q460D) were fully compared. Finally, the predicted hysteretic behaviors of different steels with both cyclic constitutive model and ideal elastic-plastic model were compared to further discuss the significant effect of constitutive relationship on members and structures. The results show that the monotonic and cyclic tensile-to-yield ratios of low yield point steels are more than 2.0~3.0, 2.0~3.0 times of normal strength steel and high strength steel. Meanwhile, low yield point steels have better ductility and energy dissipation capacity. Because low yield point steels have obvious isotropic behaviors, significant difference is observed between the calculated results using cyclic constitutive model and ideal elastic plastic model. Therefore, for structural analysis, an appropriate constitutive relationship should be adopted according to different steels.