Overseas seismic design codes of wharfs commonly utilize earthquake-induced permanent deformation for the stability analysis of bank slope，and the deformation is determined by empirical formula or charts，which are established based on the Newmark’s sliding block method. However，there is no similar method in the seismic design codes for water transport engineering in China. Thus，the Newmark’s sliding block method is conducted to analyze 3，600 artificial seismic waves which fitting the response spectrum of the seismic design code for water transport engineering in China，and the statistical characteristics and distribution of block displacements are determined. Therefore，a simple analysis method is proposed，and the implementation process of the method is illustrated by a case of a real wharf bank slope. The results show that：1）The mean value of permanent deformation determined based on the Newmark’s sliding block method is a function of yield acceleration of the bank slope. The coefficient of variation is a function of the ratio of yield acceleration to the peak ground acceleration. The permanent deformation obeys a logarithmic normal distribution.2）The stability of the bank slope can be analyzed by directly comparing the mean permanent deformation calculated by proposed equation with the specified limited value，or by calculating the deformation value under a certain guarantee rate to conduct the corresponding stability analysis.