Aiming at the problem that the high temperature of deep coal seam will affect the deep in-situ artificial coal breaking technology, the long flame coal in Fuxin Basin of Liaoning Province is taken as the research object, and the coal sample is given multiple initial temperatures and subjected to liquid nitrogen cycle freezing and thawing. The physical and mechanical properties of coal sample structure damage are studied by the change values of joint width, overall pore volume and uniaxial compressive strength of coal sample surface after unloading. The mechanical model of high temperature coal freeze-thaw cycle is established to reveal the mechanism of temperature stress caused by liquid nitrogen freeze-thaw cycles on the structural damage of coal samples at different initial temperatures. The results show that the overall structure of coal samples with different initial temperatures has different degrees of damage after liquid nitrogen cycle freeze-thaw. The higher the initial temperature, the greater the temperature stress, the greater the deterioration of physical and mechanical properties of coal samples, and the shorter the macroscopic failure cycle. The research results can supplement and improve the fluidized mining technology.