Abstract: In order to study the specific influencing factors of coal permeability enhancement under the action of supercritical CO2, this paper uses the control variable method to change the factors such as gas pressure, temperature and time of coal permeability enhancement during the experiment, and discusses the best effect of the above factors on coal permeability enhancement by supercritical CO2. The experimental results show that the effect of supercritical CO2 reaches the peak value when the action time of supercritical CO2 is 10 h, and the reason is analyzed: after 10 h of extraction, supercritical CO2 fully contacts with the coal body, and the lipids and organic compounds and hydrocarbons inside the coal body are completely extracted; under the condition of certain action time and temperature, the effect of action pressure at 9.5 MPa is the best, and the permeability reaches to the maximum when the action time and pressure are fixed, with the increase of temperature, the permeability of coal body increases first and then decreases after the action of supercritical CO2. When the action temperature is 45 ℃, it reaches the maximum value.