The Zhacang geothermal field on the east side of Gonghe basin in the northeastern Tibetan- Himalayan orogen, China, is a key region for discussing the origin of geothermal resources in the Gonghe basin. By integrating regional geological, rock thermal, isotopic chronological and geophysical testing, this paper focuses on the relationship between tectonic background and heat source mechanism of the Gonghe basin, and discusses key points of geothermal energy system in the Gonghe basin. The achievements of this study include: ① identification of high- conductors at a depth of 15 km in the crust that could be compared with the low- velocity high- conductivity layer developed in the middle- lower crust of the northeastern margin of the Cenozoic Qinghai- Tibet Plateau; ② recognition that the NW- NS strike left- lateral slip thrust fault of the Waligong near is an important heat- and conductivity controlling fault in the Zhacang geothermal field; ③ identification of a significant difference in thermal conductivity between the Mesozoic granite and the Cenozoic sedimentary cover; ④ evidence from isotopic data that the geothermal reservoir fluid are dominantly recharged by surface water; ⑤ identification of occurrence of geothermal anomalies as shallow mid- lower temperature hydrothermal reservoir in the Cenozoic sedimentary and deep higher temperature reservoir of granitic hot dry rocks. Based on the comprehensive data, we propose a geological mode of the heat source and accumulation for the hot dry rock in the Gonghe basin. A crustal higher temperature ductile layer characterized by lower resistivity and higher conductivity developed in the middle- lower crust beneath the Gonghe basin and northeastern margin of the Tibetan Plateau acts as dominant heat source; the late Triassic granite acts as a thermal conductor and reservoir, and the Cenozoic sediments act as cover layer because of its lower thermal conductivity. Meanwhile, a local hydrothermal system is formed along the active fault because of the fracture cutting across the Zhacang geothermal field.