The invention discloses a gas extraction presplitting blasting explosive automatic filling device, which belongs to the field of gas, and comprises a base, a shell is arranged on the base, an explosive storage box is arranged in the shell, a plug is arranged at the outlet end of the explosive storage box, the plug is connected with one end of a first telescopic rod, and the other end of the first telescopic rod is fixedly arranged on the inner wall of the shell; a vertical lifting column is arranged on the base, a rotating joint is arranged at the top end of the vertical lifting column, the upper surface of the rotating joint is connected with one end of a horizontal telescopic column, the other end of the horizontal telescopic column is movably connected with a mounting box body, a mechanical claw is mounted on the mounting box body, a support is arranged on the mounting box body, and a second telescopic rod is mounted on the support. And a push block is arranged on the second telescopic rod. During gas extraction, through automatic filling of presplitting blasting explosives, manual operation is avoided, time and labor are saved, the danger of explosive explosion is reduced, meanwhile, potential safety hazards such as rock stratum collapse are avoided, the working safety of the device is improved, and the device is convenient to use.