The invention discloses a drilling, air compression, drainage and hole sealing method for down penetrating layer of high-level suction roadway. The method comprises the steps of (a) drilling the penetrating layer for a drill hole, and recording an actual drilling depth; (b) inserting an extraction pipe and pressure ventilation pipe into the penetrating layer drill hole; (c) compressing air into the penetrating layer drill hole by the extraction pipe and the pressure ventilation pipe by external pressure ventilation equipment, stopping air compression when the discharged water quantity is obviously reduced and accumulated slag is discharged, and omitting connection of the extraction pipe and the pressure ventilation equipment; (d) arranging an inner bag in a coal layer top plate, arrangingan outer bag at a position far away from the inner bag by 8 millimeters, and implementing hole sealing; (f) connecting the extraction pipe and a gas suction pipe; and (g) continuously extracting gas in the penetrating layer drill hole by 10 days, and repeating operation according to the step (e) and the step (f) until the gas extraction concentration is larger than 10% if the gas extraction concentration is lower than 10% during extraction. The mutual matching of the extraction pipe and the pressure ventilation pipe is fully utilized, and the gas suction efficiency underground coal mine is improved.