Through ground temperature monitoring, identification of aquifer structures and lithologic structures, this paper analyzes the characteristics of ground temperature field and the distribution law of thermal reservoirs in the western slope region of the Yinchuan plain, determines the random variables of thermal storage, and uses Monte Carlo statistical means such as the frequency distribution and the triangular distribution to identify the parameters of random variables, and calculates the amount of geothermal resources in typical areas by means of thermal storage method. The research results show that the geothermal field of the Yinchuan plain is a deep- cycle low- temperature and low- temperature conductive geothermal system, which is divided into 5 tectonic zones (Western Slope Area, Central Deep Area, Eastern Slope Depression Area, Eastern Slope Rise Area and Southern Slope Area) and 4 thermal reservoirs (the Neogene Gangouhe Formation and the Hongliugou Formation, the Paleogene Qingshuiying Formation, the Ordovician Majiagou Formation). There is a positive correlation between the temperature of vertical ground temperature field and the depth of formations in the study area. The geothermal resources are abundant in this area, and the main thermal reservoirs are located at the 400~800m. The random variables are thermal storage temperature, rock porosity, rock specific heat capacity and rock density. The geothermal resources of western slope with temperature random frequency of 25%, 50%, 75% and 97. 5% range from 175. 56×10↑14 kJ to 230. 04×10↑14 kJ, among which the frequency of 75% can be selected as the optimal choice for the temperature random variable in the study area. The standard deviation between the geothermal resources reserves and the thermal storage method stratification calculation results is only 4. 21%. The strong spatial variation of thermal reservoir parameters can be overcome by using thermal storage characteristic analysis and Monte Carlo method parameter identification, which provides a novel method for rapid and accurate evaluation, scientific exploitation and utilization of the geothermal resources.