The invention relates to the technical field of mining equipment, and discloses an opening device and method for disassembling a mining wind and water pipeline flange. The device comprises a first supporting beam, a second supporting beam, an opening tool, a force applying rod and a pipe clamp, wherein the pipe clamp comprises a fixed section and a connecting section which are matched with the pipe diameter of a pipeline, the connecting section is fixedly connected with the two ends of the first supporting beam and the two ends of the second supporting beam correspondingly, the second supporting beam is movably connected with the opening tool, the first supporting beam is movably connected with the force applying rod, the opening tool is located between the fixing section and the force applying rod, the axis direction of the opening tool is consistent with the axis direction of the force applying rod, the tool tail is aligned with the end of the force applying rod, and the pipe clamp is used for fixing the first supporting beam and the second supporting beam with the flange. The opening device is small in size and easy and convenient to operate, can quickly open the flange which isdifficult to disassemble in various environments, saves time and labor, effectively avoids the cost increase caused by factors such as operation space limitation, and effectively guarantees the safeand stable production processes of air supply, water supply, drainage and the like of the working surface.