There are several important factors that affect the evaluation of geothermal resources, such as heat source, thermal reservoir (sand thickness, porosity, permeability), geothermal field, etc. This paper considers the Yanchang Petroleum Xihua District of the Xi an sag as an example, and analyzes the geothermal field characteristics, thermal reservoir characteristics and geothermal resources by using formation temperature measurement, well logging, and core analysis data. We also use a variety of parameters to optimize the evaluation of the favorable areas of the thermal reservoir. The research results show that the geothermal gradient of the Yanchang Petroleum Xihua District is 3. 56 ℃/100 m, which is a geothermal anomaly area. The Zhangjiapo and Lantian Bahe Formations in the Xihua District have developed interbeds of sand and mudstone, with sand thickness ranging from 40~140 m, and average porosity at 15. 68%~30. 3%. The sand thickness, formation heat, water content and total heat of the LantianBahe Formation is higher than those in the Sanmen and Zhangjiapo Formations, and the geothermal development conditions are the best. The Lantian Bahe Formation should be selected as the target stratum for geothermal development in the Xihua District of Xi an sag. The optimal geothermal development method should adopt the balance method of mining and irrigation for geothermal exploitation, and it is more appropriate to choose the underground heat transfer method of medium and deep buried pipes for geothermal resource development in the research area.