Abstract: In order to control the spontaneous fire in the goaf, CO2 is used to study the prevention and control of the spontaneous fire in the coal mine. Combined with the actual situation of the spontaneous fire in the goaf at the back of the 150201 fully mechanized top coal caving face, this paper expounds the performance parameters and technical process of the relevant equipment of the large flow gaseous CO2 fire prevention and extinguishing system, and calculates the appropriate air volume of the working face, as well as the air injection volume, air injection intensity, air injection mode and air injection pressure in the goaf, which is the large flow gaseous. The results show that: the large flow gaseous CO2 fire-fighting system has a large gas production, which can fully meet the requirements of coal mine underground goaf fire-fighting work; the technological parameters of CO2 gas injection are similar to those of N2 injection, and on the premise that the CO2 pipeline release port is located in the oxidation zone of goaf, no CO2 gas will flow from the working face; liquid CO2 is a by-product of chemical plant, with a relatively low cost, is advantageous in the coal mine underground fire prevention work promotion application.