The invention discloses a prefabricated crack hydraulic fracturing, roof-cutting and pressure-relief construction method and a drilling machine. The prefabricated crack hydraulic fracturing, roof-cutting and pressure-relief construction method comprises the steps that drilled holes are constructed in a roof above coal pillars at regular intervals, and a special drill bit is adopted to construct grooves in the axial direction at regular intervals; packers and pre-opening rubber membranes are inserted, thus the grooves are located in a packing section, and openings of the rubber membranes and the grooves are aligned, then water is injected into the packing section, the packers are pressurized by a manual pump, and whether the pressure in the packing section is decreased or not or whether thewater flows out of the packing section or not is observed; and a high-pressure pump is connected for fracturing, and prefabricated crack directional hydraulic fracturing, roof-cutting and pressure-relief operation is completed. Through the implementation mode, stress of roadway surrounding rock can be effectively lowered, roadway deformation is controlled, the safety and efficiency of resource exploitation are improved, and the problems of underground secondary pollution, poor safety and high cost which are caused by a traditional blasting technology are solved.