Abstract: The movement tracks of inclusions in liquid steel in the tundish with a filter and the inclusion removal rate during continuous casting were studied by numerical simulations through constructing a multiphase flow model. This model was testified by sampling at the inlet and outlet of the tundish during continuous casting in a steel mill. Afterward the samples were investigated by bulk-sample-electrolysis to get the proportion of inclusions in liquid steel, and the effect of casting process on the inclusion removal rate was analyzed. It is shown that the velocity of inclusions decreases due to filtering, and the residence time of inclusions in the tundish prolongs, leading to an increase in the probability of inclusion removal, so filters can increase the inclusion removal rate. Fluctuations in inclusion removal rate are found when the diameter of inclusions is less than 80 μm, however the fluctuations are not so severely for inclusions whose diameter is more than 100 μm. There occurs even the increasing of inclusions at the outlet when the diameter of inclusions is less than 20 μm during the later period of casting. The inclusion removal is a transient process.