Abstract: Niutuozhen geothermal field is located in North China, one of China's most important medium−low temperature geothermal fields. To reveal the deep structure and the origin of the geothermal field, an E−W deep reflection seismic profile which is 40 km long and 250 times folded was aquired by the Chinese Academy of Geological Sciences in 2020. The shallow strata feature in low porosity in Niutuozhen overlaid on the thermal reservoir, acts as a serviceable cap layer. Niutuozhen has a superior geothermal reservoir attributed to the evolved carbonate rocks, such as the Jixian System, and the Changcheng System, which feature high permeability. The deep−seated Niudong and Rongdong faults unequivocally extend to the basement and connect the deep thermal reservoir and shallow strata. They act as channels for the upward migration of hot water and the thermal convection process. The decollement within the crust at depths of 16 km to 20 km in the Niutuozhen Uplift serves as a thermal conductor and hydrological barrier, facilitating the conduction of heat from deeper sources to heat the reservoirs. In the seismic profile, the transparent zone revealed as intrusive bodies formed by the upwelling of the Early Paleogene asthenosphere, and the intrusive bodies extending from the lower crust below the Moho surface primarily cause the heat anomaly in the region. The shallow sedimentary cover, the Mesoproterozoic carbonatite reservoirs with well developed fracture, the conduction of water and heat through faults, the impermeable heat-conductive decollement within the crust, and the deep intrusive bodies providing a heat source, all these essential elements are combined to form the Niutuozhen geothermal field, which now has objective geothermal resources.