Abstract: With numerical simulation and industrial experiments,inclusions movement behavior in tundish under non-isothermal condition had been analyzed. Numerical simulation indicates that inclusions with different sizes tend to separate after ladle changing during continuous casting process,and inclusions with size lower than 50 μm are getting difficult to remove. During the middle and later period of casting process,inclusions with size lower than 50 μm tend to move along tundish bottom,and inclusions removing condition further worsens. Industrial experiments results show that by means of argon-blowing at tundish bottom,inclusions removing condition is improved. Average T.[O] content in tundish is reduced by 3.5 ppm,and nitrogen content is reduced by 3ppm.Before argon-blowing,inclusions quantity density of slab is about 0.008 8/mm², and reduced to 0.002 5/mm².after argon-blowing.