Abstract: To study the mesoscopic pore structure of coal shale rock under different temperatures, Micron CT scanning test was carried out on coal and rock samples at thermal fracture temperatures of 20, 100, 300 and 500 ℃. Based on the threshold segmentation algorithm, the three-dimensional pore reconstruction model is obtained, and the relationship between the pore ratio, pore throat size parameters and the quantitative index of pore connectivity with temperature is analyzed. The results show that the two-dimensional sections of coal and rock are obtained by CT scanning technology, and the three-dimensional pore structure model can be obtained by reconstruction. The relationship between porosity and temperature was exponential. The maximum pore throat length L and average pore throat radius R increase slowly and then rapidly with the increase of temperature. The pore connectivity of coal shale increased rapidly in the initial stage with the increase of ambient temperature, slowly increased in the middle stage, and decreased in the later stage.