Abstract: The northern area of Ningdu Country is rich in geothermal resources; nevertheless, the blank research on terrestrial heat flow and geothermal mineralization background restricts the exploitation and utilization of geothermal resources seriously.Based on previous research and geological survey, the authors analyzed the terrestrial heat flow and geothermal genesis mechanism of the study area.The conclusions are as follows:firstly, based on well temperature measurement and thermal conductivity data, the authors detected that the average terrestrial heat flow is 93.6 mW/m² in this region, which is far higher than the average terrestrial heat flow 62.5 mW/m² in China's continental regions.This area has a relatively strong strength of geothermal background.Secondly, the average radiation heat generation rate of the exposed granite and migmatite in this area is 6.47 W/m³, suggesting a highly radioactive rock mass.The radioactive decay heat generation of the rock is an important reason for high terrestrial heat flow in this area.Besides heating from mantle source, shell source heat generation is added to provide a stable heat source.On the other hand, two deep faults and their secondary faults across this region has provided heat transfer and water flowing channels for deep circulation of hot groundwater.Therefore, it is inferred that the formation mechanism of geothermal resources in the research area could be described as the "high heat flow background + rocks with high heat production +multi-level thermal control and water conducted faults ".This study provides guidance for geothermal prospecting in Gannan area.