Overground/underground combined pressure relief outburst elimination coal seam rapid channel digging method

The invention discloses an overground/underground combined pressure relief outburst elimination coal seam rapid channel digging method comprising the following steps: drilling a vertical shaft (3) on a ground (2) portion of a target coal seam (1), and using a high pressure hydraulic fracturing pump to reconstruct the target coal seam (1); arranging a ground gas extraction apparatus on the ground vertical shaft (3), and carrying out gas extraction process for the target coal seam (1); reasonably drilling holes and extraction holes (5) on a target coal seam (1) digging channel work plane (4), and arranging an underground gas extraction apparatus to carry out secondary gas extraction process for the target coal seam (1) until coal seam gas content and pressure to be under a safety exploitation standard; carrying out rapid channel digging for the pressure relief outburst elimination coal seam. The invention provides a novel method for rapidly digging channel in the low permeability high outburst coal seam.