Abstract: Based on the feasibility analysis and quantitative analysis of strengthening methods of frame beam after fire,the paper suggests a scientific strengthening method,i.e.,the carbon fiber reinforced polymer(CFRP).The paper then expounds the design and calculation of the strengthening with CFRP,the fire prevention and heat insulation with thin sheet,and the construction technology,etc.It is made a on-the-site static load test of frame beam before and after reinforcement,it is also examined and analysed the mechanical properties and deformation performance of the frame beam by comparing the bearing capacity,crack width and deflection.The research results show that frame beam with CFRP can improve the flexural capacity and shear-carrying capacity,delay the time of crack and minimize the crack width and deflection,which can ensure the security,applicability and durability.