Abstract: ex-situ thermal pile desorption technology has been developed rapidly because of its advantages of less secondary pollution, high pollutant removal rate and short treatment cycle. Soil moisture is the key factor affecting soil temperature rise in the process of pile thermal restoration. However, the mechanism of heat and moisture migration is still unclear, and engineering design mainly depends on practical experience. In this study, the sand loam in a polluted site in Shandong Province was used to carry out the experiment of heat and moisture transfer in heaps. Combined with COMSOL simulation, the variation rules of soil temperature and humidity in vertical and horizontal directions during the heating process were systematically analyzed. The results showed that the soil moisture near the heat source increased gradually and appeared a short peak value (10.9% higher than the initial value) and then decreased. The peak value of soil moisture increased with the increase of temperature; The higher the heat source temperature is, the more obvious the convection and diffusion of water vapor in the soil is. When the heat source temperature rises from 50℃ to 100℃, the water content at the monitoring point decreases from 4.5% to 27.2%, and the concentration diffusion mechanism of water vapor plays a dominant role in the water transfer process; For the same heat source, the soil with higher initial volume water content has relatively higher temperature change. When the initial volume water content changes from 0.07m³/ m³ Raise to 0.16m³/ m³ The temperature of the monitoring point rises from 37.1℃ to 40.0℃, and the convection heat transfer and heat conduction play a more significant role in the temperature rise process, in which the heat conduction between porous substrates plays a dominant role. The research results can provide theoretical support for the study of heat and moisture migration in the process of reactor thermal pile desorption.