Abstract: In order to analyze the desorption characteristics of gas in coal and shale, taking black shale of Longmaxi in Sichuan basin and anthracite coal of Nantong Coal Mine in Chongqing as subjects, the adsorption / desorption device was used to the experimental research which was carried out under different temperatures. The results showed that the gas desorption rate is very fast at first but decreases slowly as time goes on, and the amount of desorption eventually reaches its maximum. With the increase of temperature, the final desorption of gas increases, the increase of coal desorption is obviously larger than that of shale. Desorption quantity and desorption time of coal are greater than shale under the same condition. On the contrary, the desorption rate of shale is faster than that of coal. Based on the permeability model, the desorption process was divided into four stages: very fast desorption, fast desorption, slow desorption and very slow desorption by introducing the concept of curvature.