Abstract: Thermal groundwater resources in Chongqing are relatively abundant and the occurrence of the geothermal water is unique. In this paper, the occurrence, hydrochemical features, geothermal reservoir structure, formation conditions and genetic modes of the thermal groundwater in Chongqing are described. The geothermal reservoirs consist of the Lower and Middle Triassic carbonates. The occurrence of thermal groundwater in Chongqing is controlled by anticlines and is different from that of the common fault-deep circulation controlled by faults. The hot springs mainly exist in the axis, the two flanks and the plunging end of the anticlines. The type of geothermal water occurrence is of the basin-outcropping type. The temperature of the hot water ranges from 32 ℃ to 64 ℃ and the hot springs are of middle-to-low temperature water. Affected by the anticline structures, incongruent dissolution of the carbonates of the Lower Triassic Jialingjiang and Middle Triassic Leikoupo Groups occur. The TDS of the geothermal water are 2-3 g/L and hydrochemical types are mainly of SO4—Ca type. The hot water tends to be fresh owing to the long-term incongruent dissolution of the carbonates, but has not yet reached the freshwater stage. The geothermal water receives heat from the normal heat flow and is of meteoric origin. Groundwater receives recharge from precipitation in the recharge areas (i.e., the outcropping areas of the carbonates in the cores of the anticlines with elevation of approximately 670-1 500 m), flows along the carbonates in two flanks of the anticlines to the deep parts. After heated, the hot water flows along the anticlines from both north and south to the middle parts of the cores or to the plunging ends of the anticlines and issues in the form of the hot springs. Geothermal wells and tunnels also reveal hot water in the two flanks of the anticlines.