Firstly, we used a mooring system to investigate the seasonal variation of subsurface cold water mass in Bering Sea and analyze the variation of subsurface cold water mass in the whole subarctic Pacific. In Bering Sea, the near-surface water is highly stratified due to surface warming and the remaining cold winter water in the subsurface layer, downward propagation of wind-generated NIWs is reported for the first time by the mooring system. It is found that in summertime the energetic wind-generated NIWs are constrained to the region of strong near-surface stratification, whereas in wintertime the NIWs can propagate into deep depths. This phenomenon is important for understanding NIW-induced mixing, upward heat transfer, and sea-ice melting in the subarctic and the broader Arctic Ocean.