Abstract: The stress,strain and internal forces in possible destroyed sections of reinforced concrete members in fire are analyzed and the ultimate bearing capability program is compiled. The method of numerical calculation is proposed and the section ultimate bearing capability of reinforced members in fire at any time can be obtained by the above method and program. The mutual action relationship of ultimate bearing capability of concrete frame beam and column subjected to uniform fire are analyzed and discussed. The ductility principle of strong column with weak beam in uniform fire resistant design is proposed,which provides reference for collapse-resistant and anti-fire design.