Abstract: The nonlinear static analysis method or Pushover analysis method, coinciding with the response spectrum, is of the methods developed in recent years for quantifying the displacements and has been widely applied to seismic design for the open type wharf with standing piles. The factors influencing the estimation outcome by this method is clarified, and the qualitative and quantitative analyses are made between the capacity spectrum method and N2 method as well as the linearization procedures, equivalent damping ratio equations and response spectra used in the capacity method. A case study of the open type wharf with standing piles is conducted for the target displacement estimation to investigate the influences of the above mentioned factors. The analysis results show that there exist differences between the outcomes of the capacity method and N2 method and that the extension depends on the equivalent damping ratio equations used in the capacity method. For the capacity spectrum method, a great discrepancy arises from the equivalent damping ratio equations and the shape of descent branch of the response spectra, and the linearization method of Pushover curve has played a minor role, that has no great influence upon the calculated results for the displacements.