The circulation and mixing in the region of Prydz Bay, Antarctica were studied on the basis of the hydrographical data acquired from the Seventh Chinese National Antarctic Research Expedition (1990/1991). The main results are: (1)In the observed region,the Antarctic Divergence is located within the range of 60°30′-66°S, and is the boundary between the Antarctic Circumpolar Current (ACC) and the Antarctic Coastal Current (AACC). (2) The eastward ACC consists of both barotropic and baroclinic components having the same order of magnitude. (3) The westward AACC driven mainly by east winds is barotropic with its speed of 5-10cm/s. (4)In the 63-64°S region of the 73°E section the geostrophic currents at the surface layer (0-32.5m) and subsurface layer (32.5m-112.5m) had opposite directions, which seems to indicate that there was a kind of internal wave propagating vertically in January, 1991.(5)In the study area the 68°-73°E and 98°-108°E region were the strong mixing area due to vertical convection between the Circumpolar Deep Water and Antarctic Shelf Water, which produced heavier water(σt=27.90)down to below 800m.