On the basis of the study of the geology and production conditions and the construction method of large cross section open-off cut for fully mechanized mining face under the thin bed compound roof, A combined support has been put forward. The anchor parameters, such as the diameter and length of bolt or cable, and the spans, between-row spaces, anchor lengths and anchor forces of bolts and cables, etc., have been systematically designed by using engineering analogical design method and numerical calculation design method. The monitored results of roof separation have indicated that the anchor way and the anchor parameters provided by this paper can effectively control the roof deformation and caving of large cross section open-off cut with thin bed compound roof.