The present geothermal field is a comprehensive reaction of tectonic activity and lithospheric thermal state, which is of great significance to the study of regional tectonic evolution, deep lithospheric structure, and hydrocarbon potential evaluation of basins. Geothermal gradient and heat flow are two basic physical parameters to characterize the thermal status of sedimentary basins. Although geothermal data in mainland China is abundant and has been compiled four times, geothermal data for basins in China’s offshore and adjacent areas are rarely reported and have not even been systematically sorted out. In this paper, we calculated 810 geothermal gradient data based on newly added drilling temperature of offshore basins in recent years and collected the geothermal data from published databases and journals. With these data, we firstly compiled the geothermal gradient and heat flow in China seas and adjacent areas, and then, draw the geothermal gradient and heat flow contour maps for basins in China’s offshore and adjacent areas. Moreover, we summed up the present geothermal field characteristics and analyzed its influence factor. The results show that the average geothermal gradient and heat flow of basins in China’s offshore and adjacent areas are 43.2±25.7 ℃/km and 74.4±26.6 mW/m2, respectively. Most of those basins have an average heat flow higher than 65 mW/m2, thus can be sorted into the “hot basin”. Generally, the present geothermal field of offshore basins is characterized by “two zones”, in which the nearshore zone is cold and the far shore zone is relatively hot. The regional tectonic setting influenced the present geothermal field in the study area. The Lithosphere extension and thinning resulted from the interaction of the Eurasian Plate, Indo- Australian plate, Pacific plate, and Philippine Plate multiple control the overall characteristics, while the local thermal anomalies might be ascribed to fault activity, magmatic activity, and mud- heat flow diapir activities.