Abstract: A kind of filter with sand as the percolation medium for dust-removing were discussed and designed for isothermal experiment. Through the experiment by this fiter simulating the BF top gas sub-dedusting, the effect of the thickness of the fiter layer and the filtration gas velocity upon the dust-removing efficiency and the pressure loss was investigated. Based on the experimental results, the optimized thickness of the filter layer and the optimized velocity of filtration gas were confirmed.