In this paper, Nonlinear Static Pushover analysis method(NSP) is proposed which apply to RC buildings reinforced by external retrofit fornseismic performance. Based on previous analysis and research, NSP is more developed by connection nonlinearity according to shearnresistance mechanism such as dowel and adhesive resistance as major shear resistance elements. According to the proposed method,nstructural analysis for example buildings was carried out to evaluate seismic performance of buildings. And, it was confirmed thatndepending on shear strain and characteristics of joint resistant of external retrofitting are different from internal retrofitting. Furthermore,nthe strength reduction coefficient of the anchor needs to be considered at the joint design.