Abstract: Because of poor permeability and low gas extraction rate of Ⅱ₁ coal seam at Wang-xing Village mine,the hydraulic fracturing permeability improvement technology is proposed.The mechanism on permeability improvement by hydraulic fracturing is analyzed,then the process and parameters of hydraulic fracturing are determined.Finally,hydraulic fracturing experiment was conducted at 11091 haulage roadway of Ⅱ₁ coal seam.Results showed that the average concentration of gas extraction increased 5.3 times and the total quantity of gas extraction increased 6.1 times after the implementation of hydraulic fracturing.Consequently,the technology of hydraulic fracturing has perfect effects on improvement of permeability and gas extraction rate.