The combination of wellbore high temperature heating technology with horizontal wells can increase the productivity of gas wells by increasing the drainage area. In order to study the permeability of rock mass in complex underground environment, this paper carried out a heating test for 5 days in a 5.4 m × 0.6 m × 0.6 m simulated tight sandstone well section. The pressure-decay method was used to evaluate the change of tight sandstone permeability during borehole heating (room temperature ~ 600 °C) and cooling. The results indicate: (1) The pressure decay time decreases from 68.8 to 18.6% with heating, and increases to 48.9% after cooling, showing a fast-slow-fast decay trend. (2) The overall change of permeability shows an “S” shape, which can be divided into three stages: the increase rate is about 0.15 mD/d at the initial stage of heating; after 24 h heating, the rise is slow, with an increase of about 0.03 mD/d; after cooling, it rise rapidly, with an increase of about 0.2 mD/d. (3) According to the numerical model of thermal-fluid-solid coupling constructed, it can be seen that heating first makes the originally invaded water phase escape, and the water lock damage is relieved. With the accumulation of heating time, the tensile and compressive stress fields increase, but the rock mass are not destroyed in general. After cooling, the inner tensile stress of the rock mass re-accumulates and reaches the failure strength of the rock mass, resulting in cracking. The research results are helpful to further understand the occurrence mechanism and critical conditions of mesoscopic damage and macroscopic cracking of rock mass under thermodynamic coupling.