In order to explore the energy conversion in the process of CO2 outburst, taking the second layer coal sample of Jinhe Coal Mine in Yaojie Mining Area of Gansu Province as the research object, the simulation experiment of CO2 dynamic effect under different pressures was carried out, and the energy conversion in the process of outburst was analyzed. The results show that the gas internal energy composed of adsorption gas desorption expansion energy and free gas expansion energy is the main energy source of outburst, most of which is used for coal crushing, and a small part is used for coal throwing. The D-A model with micropore filling is more accurate in calculating CO2 adsorption capacity. The research results will further enrich the basic theory of CO2 outburst disaster prevention.