In coal,the gas mainly exists in a free or an adsorption state.When the coal containing gas is damaged,gas desorption and diffusion will occur which can result in gas disaster.This research on gas desorption and diffusion provides a theoretical basis for gas disaster mechanism and prevention.The influence of pressure and temperature on gas diffusion is studied by the experiment.And the mechanism of pressure and temperature on gas diffusion is also analysed.The research results indicate that gas diffusion capacity increases with increasing temperature under the same pressure for the same coal sample.This is mainly because the temperature increases,gas molecular hot motion is severer,kinetic energy of gas molecular increases,and gas desorption quickens,therefore gas diffusion capacity changes stronger.Under other unchanged conditions,the greater gas adsorption balance pressure,the more gas adsorption content,and the higher the initial gas concentration.When gas diffusion begins,the greater the gas concentration gradient,the faster the gas diffusion speeds. In coal, the gas mainly exists in a free or an adsorption state. When the coal contains gas is damaged, gas desorption and diffusion will occur which can result in gas disaster. This research on gas desorption and diffusion provides a theoretical basis for gas disaster mechanism and prevention. The influence of pressure and temperature on gas diffusion is studied by the experiment. And the mechanism of pressure and temperature on gas diffusion is also analysed. the research results indicate that that gas diffusion capacity increases with increasing temperature under the same pressure for the same coal sample. This is mainly because of temperature increases, gas molecular hot motion is severer, kinetic energy of gas increases, gas desorption quickens, gas permeability capacity change stronger. Under other unchanged conditions, the greater gas adsorption balance pressure , the more gas adsorption content, and the higher the initial gas concentration er the gas concentration gradient, the faster the gas diffusion speeds.