Liquid CO₂ presplitting permeability improvement technology was used in Shimen mining, which could change coal seam permeability and porosity of coal seam to improve mining rate. The technology was applied in return air inclined roadway of Yuxi Mine, with bedding drilling and gas pre-drainage. The result showed that drilling drainage quantity was improved, decay time was extended, drilling working was reduced, drainage cycle was shortened, which realized eliminating burst danger and safe mining, with great reference and promotion value.