Abstract: Underground coal gasification (UCG) is a kind of low-carbon utilization technology of coal resources,which has a good prospect in China’s low-carbon economy.However,the global underground coal gasification has experienced several decades of field tests,and there are still many problems to be solved.In the underground coal gasification process,the gasification zone growth with crack extension inside the coal seam.It will lead to excessive destruction of coal seam roof strata,resulting in gas leakage,surface subsidence,water pollution and other problems,if the gasification zone cannot be effectively monitored and controlled.To this end,it is proposed to evaluate the rupture and evolution of coal during gasification based on acoustic emission parameters and variation laws.The effects of temperature,the direction of the stratified plane,and the inherent microcracks on the coal fracture and crack extension were investigated by some heating experiments with plate-shaped and cylindrical coal specimens.To monitor the failure process and to measure the microcrack distribution inside the coal specimen before and after heating,the acoustic emission (AE)analysis and the X-ray CT were applied.The results show that in the process of heating the surface of the coal sample,many cracks and fissures will be produced on the surface and inside of the coal sample,and a large number of acoustic emission signals will be released.The faster the heating temperature changes,the higher the acoustic emission activity,the more microcracks are produced,and the direction of microcracks in the coal sample tends to be parallel to the coal seam surface.A laboratory-scale UCG model experiment was conducted with set design and operating parameters.The temperature profiles,AE activities,product gas components as well as the gasifier weight loss were measured successively during gasification.It reveals the intrinsic relationship between the evolution of internal fissures and acoustic emission,and it proves that the acoustic emission monitoring technology can predict and evaluate the fracture and evolution area of coal and rock mass in the gasification process.