In this paper, the supply of thermal environment regulation service is depicted by the InVEST urban cooling model, the demand for thermal environment regulation service is depicted by the risk assessment framework, and the relationship between supply and demand and quantity is depicted by supply-demand difference model, to explore the difference between supply and demand of thermal environment regulation service in Xi’an city from the perspective of functional areas. The main conclusions are as follows. The overall supply of thermal environment regulation services in Xi’an City is poor, showing a spatial pattern of high external and low internal, and the problem of unbalanced distribution is more prominent. The supply of water areas, agricultural areas, and park green space is strong, while the supply of commercial areas, residential areas, and industrial areas is weak. The demand for thermal environment regulation services in Xi’an is low on the whole, showing a spatial pattern of low outside and high inside, and the problem of unbalanced distribution is also prominent. The demand for commercial areas, public service areas, and urban villages is strong, while the demand for water areas, agricultural areas, and park green space is weak. Nearly half of the areas in Xi’an are in a state of oversupply or supply deficit, and the problem of quantity imbalance is quite serious, showing the pattern of external surplus and internal deficit in space. Residential areas, commercial areas, industrial areas, urban villages, and traffic stations are mainly in negative equilibrium, public service areas are mainly in positive and negative equilibrium, and parks, green areas, agricultural areas, water areas, and open spaces are mainly in positive surplus.