PREP(plasma rotating electrode process) powders of 316 stainless steel were loosely sintered to fabricate porous filters. Porosity, size and structure of pores, permeability and mechanical strength of the filters were investigated with the variation of powder sizes and sintering conditions, and were discussed in conjunction with mathematical analysis. Porosity was nearly constant about 32∼34%, but mean pore size, permeability, pore structure and mechanical strength were changed markedly with sintering conditions.