The applicability and economical efficiency of slice mining,full-mechanized caving mining and full-seam mining to the extra-thick coal seams mining in Shendong mining area were analyzed respectively.The results showed that comprehensive mechanized full-seam mining is a mining method that applicable to the coal seams with thickness of about 7m.The application of this mining method in the 22303 mining face of Bulianta coal mine has achieved good economic results.