The invention relates to a
coal seam pre-splitting method based on gas extraction, which adopts a 'CO2 gas extraction device' as a tool to blast and pre-split a pre-mined
coal seam, so as to increase the crack of the
coal seam, drive out gas absorbed on the coal seam and extract the gas. The method particularly comprises the following steps: drilling a hole on the working surface of a pre-mined coal seam, filling CO2 gas extraction device into the drilled hole, sealing the drilled hole, detonating the CO2 gas extraction device, releasing high-pressure CO2 gas for deep-hole
impact and pre-splitting of the coal seam, taking out the CO2 gas extraction device, and connecting the drilled hole with a gas extraction
system to extract gas. The pre-splitting method of the invention can greatly enhance the permeability of the coal seam, promote the gas dissociation in the coal seam, and improve the underground gas extraction efficiency of the coal mine.