<p>Beam–column joint with complex mechanical behavior is an important part of reinforced concrete (RC) structures. The present study aims to assess the joint shear stress–strain relationship by adopting strut–and–tie approach of the interior beam-column subassemblages. Totally six interior RC beam–column joint specimens were tested under cyclic loading. The test results of beam–column subassemblages show that under high shear stress, the joint cores always perform obvious inelastic shear deformations. It is evident that when using finite element simulation to study the seismic behavior of RC beam–column joints, accurately modeling the shear stress–strain relationship of joint core is critical for successfully implementing the finite element analysis. Based on the experimental results, this study innovatively proposed a strut–and–tie model (STM) for RC interior beam–column joints to investigate shear behavior within joint core. This STM was established according to the deformation characteristics and the crack patterns of the joint region. The force equilibrium conditions and deformation compatibility requirements of this model were formulated. Comparisons were made between the predicted and published experimental results of the twenty–three RC interior beam-column joints with respect to joint shear stress and strain envelope curve at this state to investigate the adequacy of the proposed STM. The results demonstrate that the joint shear stress and strain envelope curves predicted by the proposed STM show closer agreement with experimental data. The mean absolute error (MAE) of peak shear stress calculated by the proposed STM is significantly lower than that of the Zhao-Yang model. The coefficient of determination (R²) is significantly higher than that of the Zhao-Yang model. These findings confirm that the proposed STM exhibits high prediction accuracy for the shear stress–strain relationship of beam-column joints.The calculation results of the proposed STM were used in finite element analysis of the beam–column joint tests based on the Beam Column Joint Element in the OpenSees software. The load–displacement hysteresis curves and joint shear deformations obtained from the finite element analysis were compared against experimental results of beam–column joints. Analytical results further validated the applicability and efficacy of the proposed STM.</p>