Nonlinear static analysis,as a widely used seismic perlormance assessment method,is used in elastic-plastic deformation analysis of structures under rare event of earthquake.Nonlinear static analysis has a number of current analytical methods,which are the same in the establishment of structural capacity curve,namely,transfer the force-displacement curve into a capacity spectrum,but different in the establishment of the demand curve.This paper introduces several typical nonlinear static analysis of establishing demand spectra methods,and reveals the difference and improvement between it and original method for establishing demand spectra.