Abstract: Zero - velocity layer is introduced into seismicmigration in area with high topographic inequality. Thispaper expounds thc implication of zero - velocity layer,implementation of zero - velocity layer in migration (bothtime migration and depth migration) in area with hightopographic inequality, its advantages over conventionalmigration and why introducing zero - velocity layer intomigration. Verification with field data shows that it is aneffective migration method in areas with high topographicinequality.