As an important space carrier to participate in global competition, the Guangdong-Hong Kong-Macao Greater Bay area is facing the pressure from the energy demand and environment protection. Developing geothermal resources is an effective way to solve the problem. In this paper, the possibility of geothermal development in Greater Bay area was reasoned, based on the analysis of regional geotectonic, stratigraphic lithology and geothermal field. Considering deep ground temperature, rock thermal physical parameters and terrestrial heat flow, geothermal water resource and hot dry rock resource were quantitatively assessed through raster units. Further, high potential geothermal zones were distinguished. Results show that:1) the intersected fault structures and widely distributed granite in the Greater Bay area provide a favorable geological environment for the storage and formation of geothermal resource, which is verified by the measured terrestrial heat flow; 2) the computing results indicates that temperature would be over 70 at depth of over 1.3 km and 168.81~233.61 at depth of 5 km, showing a high potential of geothermal resource; 3) The estimate geothermal resources in the Greater Bay area amount to 5.83×1017 kJ within the depth of 5 km. It is equivalent to the thermal value of standard coal of 5.94×109 t and can reduce the emission of CO2 by 4.04×109 t, when recovery rate is set at 30%. 4) The area of high potential geothermal resources is mainly distributed along the northeast deep fault, i.e. in Foshan, Zhongshan, Jiangmen, Shenzhen and Hong Kong, where the unit geothermal resource potential is equivalent to standard coal of 5.19×105 t per square kilometer, and should be taken as key area for geothermal prospecting and exploitation.