Abstract: As an effective approach to avoid environmental problems caused by dewatering, the design of filter material for tube well dewatering in water-rich and highly permeable strata is critical to dewatering engineering in complex urban environment. Although theory of seepage has been well developed, a rational method for determining the particle size of filter materials has not yet been established. Based on soil filtration and pressure-reduction mechanisms of filter layers, this study proposed a design criterion of tube well dewatering filter material with effective interlayer coefficient E_c=2\sim 3 and non-uniformity coefficient C_u\leqslant 2 as control indexes. Through discrete element numerical simulation, the particle loss characteristics and porosity variation of the formation-filter material system in the seepage process were analyzed. The microscopic mechanism of the filter material to achieve a self-stable state by intercepting fine particles was revealed. The results show that when the effective interlayer coefficient E_c\leqslant 3 , the fine particle loss is less than the critical value of 3%, and the porosity stabilizes accordingly. The proposed design criterion was further validated through field pumping tests. This study provides a theoretical basis for the design of tube well dewatering filter material, which can improve the safety of foundation pit dewatering projects in water-rich and highly permeable strata.