Study of data on seismic landslides caused by Wenchuan Earthquake,Luhuo Earthquake and Songpan-Pingwu Earthquake indicates that seismic landslide had caused the numerous personnel casualties and directly destroyed facilities and that frequency distribution of landslide gradients was differences between seismic landslides and rainfall landslides.The frequency distribution of seismic landslides follows the Logistic distribution.The calculation and evaluation methods for gradient distribution of typical seismic landslide and regional seismic landslide were put forward.