The Reshuiquan hot dry rock (HDR) in the Guide County, with an area of approximately 122 km2, is characterized chiefly by semielliptical shape and lies in the west of the Reguang fault which is part of Xinjie fault zone with NNW trend. The ZR1 well reflects that the upper part of the Reshuiquan HDR is a mediumtemperature hydrothermal system with selfenclosed capping properties. A relatively complete or impermeable subhigh temperature granite body is observed from 2800m to 3050m. The temperature of the stratum at 3050.68m is 151.34°C, indicates that a HDR layer is developed. This HDR reservoir is mainly composed of middlelate Triassic granite whose time intruded into the stratum is 233.2～222.3Ma. The rock types of the granite can be subdivided into diorite, granodiorite, monzonitic granite and Kfeldspar granite. The XinjieWaliguan strike slip and extrusion structural zone, marked by a regular flower structure, is a regional heat conduction channel and controls the regional distribution for the HDR. Comprehensive analysis on the magnetotelluric sounding, highresolution gravity anomaly, linear inversion of resistivity and phase velocity of Rayleigh wave group, and geology show that the heat source mechanism of the Reshuiquan HDR is most probable a compound heat source. These partial melting layers within the continental crust are the most important heat sources for this HDR. Furthermore, a superposition heat source for this HDR comes from the mantle heat flux, small melting body rising along the strikeslip fault zone during the late period, and decay of radioactive elements such as U, Th, and K within the double crust.