Under fire, the concrete structure is damaged in different degrees, which makes the bearing capacity of the component decrease continuously. It is beneficial to avoid the risk to study the bearing capacity of the rein- forced concrete structure at high temperature. A cellular automaton temperature diffusion model was established to explore the distribution of temperature field and analyze the damage of materials. In this paper, the residual bearing capacity of normal section and oblique section after the fire were analyzed through the study of three sides of fire beams and four sides of fire columns. By comparing with the finite element calculation, it is proved that the calculation model of residual bearing capacity proposed in this paper is accurate.