Abstract: In oder to better understand the new revised conditions about mine water prevention and control part from coal mine safety regulations, based on the ge neral principles of revision, according to six modifications principles, i. e, adhering to the people-oriented, strengthening the enterprise dominant position, soliding found ation status, drawing lessons from the accident, strictly working procedures, embodying the scientific and technological progress, the author ilustrates related key chan ges. Meanwhile, the author put forward mining under the roof aquifer do not belong to the category of mining with pressure, the terms about mining with roof water pres sure should be amended as mining under floor water pressure in No.302 article. There are contradictions in the calculation of the safety thickness of the aquiclude in ap pendix four and five in Prevention and Control of Coal Mine Water Regulations. The paper analyzes and demonstrates theoretically that the Slisalif formula and water in rush coefficient formula are respectively suitable for evaluation of safety thickness of aquifuge in the heading face and the working face, the water inrush cofficient for mula is suitable for the working face with the aquiclude thickness of the floor is less than 50 m.