Radium-224 activities in the western Arctic Ocean were measured via ship-board 220Rn emanation technique during the Second Chinese National Arctic Expedition. The results showed that the 224Ra activities in the study areas ranged from being less than 0.08 to 3.58 Bq/m3, with an average of 0.23 Bq/m3. The low 224Ra concentration in the surface water was attributed to the influence of sea ice melted water. The horizontal distribution of surface 224Ra in the western Arctic Ocean showed a high 224Ra characteristics occurred along the slope around 160°W, providing evidence for the importance of ice-rafted sediments to controlling the distribution of radium isotopes in the Arctic Ocean. Mostly, 224Ra concentrations increased with the depth in the shelf region and reached a maximum at 75 m at the central Canada Basin, which further confirms the importance of the transport of shelf bottom water to maintaining the upper halocline layer in the Canada Basin. Radium-224 activities in the western Arctic Ocean were measured via ship-board 220 Renation technique during the Second Chinese National Arctic Expedition. The results showed that 224Ra activities in the study areas ranged from being less than 0.08 to 3.58 Bq / m3, with an average of 0.23 Bq / m3. The low 224 Ra concentration in the surface water was attributed to the influence of sea ice melted water. The horizontal distribution of surface 224 Ra in the western Arctic Ocean showed a high 224 Ra characteristic occurred along the slope around 160 ° W, providing evidence for the importance of ice-rafted sediments to controlling the distribution of radium isotopes in the Arctic Ocean. Mostly, 224 Ra Concentration increased with the depth in the shelf region and reached a maximum at 75 m at the central Canada Basin, which further confirms the importance of the transport of shelf of bottom water to maintain the upper halocline layer in the canada basin.