Expounded the existing problems of porous filters while using clean coal technology,Gasar metal porous filter material functions were briefly introduced.A simple design calculation model was built on the basis of analyzing hydroresistance which was used as the main evaluation index of permeability of porous materials.Therefore, the formulas of hydroresistance in pores of porous materials are obtained and the advantage of hydroresistant porous metal filter materials is theoretically proved.