The randomly distributed steel fibers are added in the concrete matrix, which is results in the flexural and tensile strength significantly increased, and the shortcomings of poor toughness and low residual stress are effectively improved. This study aims to establish the new constitutive model for the steel fibers reinforced concrete(SFRC). Before the cracks occurred, the steel fiber and concrete matrix are fully bond and the two-phase composite law is used to calculate the elastic modulus of SFRC; When the concrete crack initiates and propagates, the contribution of the concrete and the steel fiber will be considered respectively. And the strengthening effect of fiber on the concrete cracked plane will be considered through the bond-slip model during the process of fiber partially debonded and fully debonded from the concrete matrix. Through Fortran programming, the proposed constitutive model is introduced into ABAQUS by using the subroutine Umat, and the finite element model is established to simulate the tensile tests and 4-points flexural tests of SFRC. The comparison of numerical simulation results and available experimental data, the accuracy of the constitutive model is verified. Meanwhile, Detailed analysis of the mechanical properties of SFRC for tensile strength, residual strength, flexural strength, and toughness.