Abstract: To accurately simulate the flexure-shear behavior and identify the failure modes of reinforced concrete (RC) bridge columns, it is essential to characterize the shear spring constitutive model. However, the determination of deformation parameters involved in this model remains unclear. To address this issue, a method for determining the shear spring constitutive, calibrated from quasi-static test data of RC columns, is proposed. The method focuses on extracting the shear deformation component from the overall flexure-shear deformation and employs regression analysis to establish fitting formulas for key deformation parameters. On this basis, accurate simulations of both flexure-shear and pure shear behaviors of RC columns are achieved. Validation against quasi-static test results of rectangular cross-section RC columns demonstrates that the proposed modeling approach can predict failure modes based on strength criteria, and the derived deformation parameter formulas exhibit high fitting accuracy.