Abstract: To investigate the post-fire mechanical behavior of solid-web steel-reinforced concrete (SRC) cross-shaped columns, nine specimens were designed to study the effects of constant high temperature and duration. Eight specimens were exposed to high temperature followed by axial compression tests, while one served as a reference specimen tested without high temperature exposure. The experiments revealed the thermal damage characteristics and axial failure modes after high temperature exposure. Parameters such as mass loss rate, cross-sectional temperature distribution, residual load-bearing capacity and deformation performance were analyzed. The results indicate that with increasing temperature and heating duration, the color of specimen surface gradually changes from bluish-gray to dark red and eventually to off-white, accompanied by denser surface cracks, a crisper tapping sound and a maximum mass loss rate of 5.95%. The axial failure modes after fire exposure are similar to those at room temperature, generally comprising elastic, elastic–plastic and failure stages. Major cracks tend to develop along the column edges in a “V”-shaped pattern. As the temperature and duration increase, the maximum reduction in residual load-bearing capacity reaches 28%, the initial axial stiffness decreases by up to 66.8%, and the deformation capacity increases by 96.6%. A significant decline in load-bearing capacity is observed when the temperature exceeds 400 ℃. Based on the test results, a calculation method for evaluating the residual axial load-bearing capacity of solid-web SRC cross-shaped columns after high temperature exposure was proposed, providing a reference for the post-fire safety assessment of such structural elements.