The invention discloses a facility for detecting the methane concentration of a coal mine. The facility comprises a case. The case comprises a front cover and a rear cover, which is matched with the front cover. The front cover and the rear cover form a cavity structure. A processor is arranged in the case. The bottom of the case is provided with a laser gas detection assembly. An alarm lamp is arranged on the surface of the laser gas detection assembly. A keyboard, a display screen, a buzzer, and a printer are arranged on the front cover. The provided facility solves the problems that a minemethane detection device cannot accurately detect methane, the detection precision is low, and the detection device needs frequent calibration. The invention provides the facility for detecting the methane concentration of a coal mine. The gas is detected by laser, the detection precision is improved, the calibration period is prolonged, the work load of calibration staff and the work for maintaining a monitoring system are largely reduced, the number of workers is reduced, the work efficiency is improved, and great economic benefits are generated.