Based on the analysis of coal seam occurrence and condition of top and floor in Dayu mine, the comprehensive mechanical of a full mining height is applied to the 103 face, and the method of all caving process is used for working face roof. According to the observation of mine pressure in the same coal seam and the mining pressure parameter statistics of the work face, the work face is supped properly from mining pressure parameter, reasonable support strength and testing of strength of support. When the coal seam is mined, the roof control and advanced support are analyzed , the safety of the mine is ensured, and economic benefits of coal mine have been raised.