Abstract: To explore the development mechanism of plastic stress and biaxial bending moment of plastic H-section steel members subjected to biaxial bending and axial force, parametric analysis models of H-section members with different axial force ratios, web and flange width-thickness ratios and different loading angles were developed in ABAQUS based on the modeling method verified against existing experimental data. Combined with the finite element analysis results, the plastic stress development law of H-section steel members under biaxial bending was investigated. The plane section assumption was introduced to simplify the stress distribution. Furthermore, the relevant parameters were obtained by the least square fitting, and the internal relations among loading displacement, plastic development degree and macroscopic bearing capacity were established. The theoretical calculation model of bidirectional bending moment of H-shaped steel members was established. The model fully considers the influence of sectional dimensions, displacement loading direction angles, axial compression ratios and loading displacement. Through the analysis of the model calculation results, it was verified that the model can obtain the stress distribution form of the component at any time of loading, and provide a simpler design method for the bidirectional bending design considering a certain degree of plastic development.