The invention provides a drilling, jam releasing and fracturing integrated device and method for a soft
coal seam. According to the device, a
drill rod is assembled on a drilling
machine, a
jet flow drill bit is installed at the outlet end of the
drill rod, and the inlet end of the drill rod is connected with an outlet of a low-temperature pump; outlets of a plurality of first
liquid nitrogen tanks in the first set of
liquid nitrogen tank group are connected with an inlet of a low-temperature pump through a first
nitrogen supply pipeline; outlets of a plurality of second
liquid nitrogen tanks in the second liquid
nitrogen tank group are connected with the main
nitrogen supply pipeline through a second nitrogen supply pipeline; a heater is arranged at the bottom of the second liquid nitrogen tank. The method comprises the steps of determining a
coal seam drilling position and an anti-reflection transformation area; arranging a drilling, jam releasing and fracturing integrated device in the rock roadway; liquid nitrogen output by the first set of liquid nitrogen tank group is pressurized by a low-temperature pump and then is conveyed into a
jet flow drill bit, and formed high-speed liquid nitrogen
jet flow acts on a
coal seam; and blocking the inlet of the
drill hole, fracturing the coal seam by using high-pressure fluid generated by liquid nitrogen
phase change, and forming cracks in the coal seam. By means of the device and method, drilling, jam releasing and fracturing operation can be integrally achieved.