The invention discloses a detachable coal seam gas coal core sampling machine. The sampling machine comprises a bottom plate, two walking positioning devices and a sampling device; the two walking positioning devices are arranged on the bottom plate; the two walking positioning devices are symmetrically mounted on the left side and the right side of the lower end of the bottom plate; an opening structure is formed in the middle of the right side of the upper end of the bottom plate; the sampling device is mounted on the left side of the upper end of the bottom plate; and the right side of thesampling device is located in the opening structure. According to the sampling machine, the difficult problems that during underground coal seam gas sampling, an existing sampling machine is inconvenient to move, poor in positioning effect, inaccurate in coal seam sampling, complex in sampling, inconvenient in operation, low in automation degree and low in working efficiency, and after sampling, the existing sampling machine cannot quickly take out coal cores in the sampling machine and effectively distinguish the coal cores, and is complex in operation, high in labor intensity and low in efficiency, and the like can be solved, so that the function of automatic quick sampling of underground coal seam can be realized.