Abstract: By the test of floor specific pressure of 2201 working face in Songshan Coal Mine, the paper obtained the floor allowable specific pressure and allowable rigidity; it is known that the floor belongs to class II loose floor. By stress analyzing of ZF2200/16/24 mechanized caving four-pillar support, the paper drew the distribution characters and the maximum value of support pedestal specific pressure. After checking, the selected support can meet the requirements of floor in 2201 working face.