To study the mechanical properties of high-strength steel T-stubs considering additional axial force under fire conditions， a numerical analysis of high-strength steel T-stubs was conducted using the finite element analysis software ABAQUS. The initial stiffness， tensile capacity， and failure modes of high-strength steel T-stubs considering additional axial force under fire conditions were obtained. The numericalanalysis results are compared with the test results to verify the numerical model.Subsequently， a parametric study was performed using the validated finite element model to examine the mechanical properties of high-strength steel T-stubs under combined tension-shear loadings under fire. The parametric study shows that with the increase of shear-tension ratio， the load-bearing capacity of the bolts becomes crucial to bear the load of high-strength steel T-stubs under the combined action of tension and shear， and the tensile load-bearing capacity and the ultimate displacement of T-stubs decrease sharply. Finally， the relational expression of the tensile force and shear force of high-strength bolts under fire conditions was deduced based on the Code for design of steel structures. The result was compared to the results obtained from the finite element simulation and experiments. The comparison shows that the relationship expression has good applicability， and it can accurately predict the tensile bearing capacity of bolts under fire conditions.