Seismic permanent displacement forecast is quite important in seismic design of landslide prevention and
control structure in earthquake zone． The stability of landslide mass itself can be directly judged from this permanent
displacement． Therefore，the critical accelerations that cause permanent displacement of landslide mass for two
types of slide，i． e． ，translation and revolution were deduced based on upper bound theorem of limit analysis． Considering
the balance relationship between seismic input energy and structural energy dissipation，the calculation
method that predict landslide permanent displacement under earthquake action was established． Finally，an example
was given to prove the reasonability of the method．