Abstract: To improve the whole seismic performance of the frame structure， especially the beam-column joint， a new seismic reinforcement method is proposed for reinforced concrete frame structure with adding a web-type plate. The internal force optimum can be achieved by setting the web-type plate at a certain region between frame beams， and the bending moment of the beam-column joint will decrease. A multiple seismic defense lines frame structure can be formed with the web-type plate. A typical frame structure of 10 stories is designed as a case study. The effects of the layout， linear stiffness ratio， and reinforcement of the web-type plate on the structural performance are analyzed. The reinforcement ratio of the web-type plate to the column and beam is proposed. The seismic analysis shows that the lateral stiffness of the structure is improved， meanwhile the bending moment of the beam-column joint is reduced. The optimum layout position of the web-type plate is 0.3 and 0.7 of the beam span， and the suggested linear stiffness ratio of the web-type plate to column and beam are 0.7~1.5 and 3.5~7， respectively. Further， a suggested reinforcement ratio of the web-type plate is given by nonlinear parametric analysis to ensure that the plate yields first as designed. The nonlinear dynamic time-history analysis of an actual engineering project that seismic upgrading with the web-type plate is undertaken. The analysis results show that the lateral displacement， and the inter-story drift ratio of the structure with web-type plate are reduced. Compared with the structure before upgrading， the plastic hinges are reduced. The seismic performance of the frame structure reinforced with the web-type plate is improved. The analysis verify that the proposed strengthening method with web-type plate was reasonable and feasible.