Abstract: This invention relates to a porous metallic honeycomb substrate for automotive exhaust gas cleaning catalysts. It is mainly a column substrate formed by sintering metal grains, with many connected fine pores between the metal grains. And there are also many through holes between the two end faces of the column. Because the sintered metal grains have constructed a rough surface, the noble metal catalysts can be coated firmly on the said porous metal honeycomb substrate and is not easy to be blown off by the vent gas. In addition, because there are many fine pores between the metal grains, the gas can contact with the catalysts effectively, and so the conversion efficiency can be improved greatly.