The 3rd Chinese National Arctic Research Expedition (CHINARE-III) was carried out from July to September in 2008. The partial pressure of CO2 (pCO2) in atmosphere and in surface sea water were determined along the cruise track in the Bering Sea during July 11-27, 2008, and a large numbers of sea water samples were taken for CO2 system parameters measurements (I.e., pH, total alkalinity (TA), total dissolved inorganic carbon (DIC)).The distributions of CO2 parameters in the Bering Sea and their controlling factors were discussed. Sea water pCO2 along the cruise track changed drastically, varying from 148 to 563 μatm. The lowest pCO2 values were observed near the Bering shelf break while the highest pCO2 existed at western Bering Strait. The Bering Sea acts as a net sink for atmospheric CO2 in summer generally. Using the average wind speed and average pCO2, the air-sea CO2 fluxes in Bering shelf, slope and basin were estimated as -9.4mmol, -16.3 m-2d-1 and -5.1 mmol m-2d-1, respectively. The annual uptake of CO2was ~34Tg C in the Bering Sea.