Abstract: As a comprehensive utilization technology of clean coal, underground coal gasification has become a strategic direction of innovation in harmless coal mining technology under the background of dual carbon. In order to study the multi-field coupling changes of coal seam overlying strata temperature field, displacement field and damage field during underground coal gasification process, based on the geological and production conditions of a underground coal gasification engineering area in Shandong Province as the research background, the formation mechanical property tests in underground coal gasification area are carried out first, and the physical and mechanical parameters and thermodynamic parameters of the rock were obtained. The reasons for assigning thermal physical parameters such as specific heat capacity were explained. A multi field coupled numerical simulation method for underground coal gasification of overlying strata was developed, which takes the maximum tensile stress criterion and Mohr-Coulomb criterion as the damage and failure criterion of rock, and takes into account the characteristics of combustion point movement, stress balance and cooling of the combustion and cavitation zones in the process of underground coal gasification. A numerical solution method for the movement and damage process of overlying strata during underground coal gasification is presented. Based on this method, the coupling evolution law of temperature field, displacement field and damage field in the gasification direction and the stratigraphic profile perpendicular to the gasification direction are studied. The results show that: In the process of underground coal gasification, the influence range of high temperature first increases and then decreases with the progress of gasification, and the propagation rate slows down. The final influence range of high temperature is 5.4 m on the roof and floor, and 4.9 m on the two sides of the roadway. After the start of the project, immediate roof has shifted upwards, indicating that high temperature has a certain degree strengthening effect on the bearing capacity of the gasification roadway roof. After the formation cools to room temperature, the vertical displacement of the coal seam immediate roof reaches 257.18 mm. With the progress of gasification project, obvious tensile damage occurs in the roof of gasification roadway, and the damage scope of the roof is larger than that of the floor and two sides. When project is carried out to the 150th day, the damage area of surrounding rock of the roadway generally presents an approximate “butterfly” distribution. At the end of underground coal gasification, the roof damage height of the No. 1 gasification roadway is 12.38 m, and the roof damage height of the No. 2 roadway is 11.14 m. The 15 m wide coal pillar designed in engineering theory can ensure the stability of the gasification mining area.