The invention relates to a magnesia foam ceramic filter with special high-temperature chemical stability, which is composed of magnesia, boron The high-quality polyurethane foam is used as the carrier, impregnated with the above slurry, extruded to form a billet, dried and sintered to obtain a magnesia foam ceramic filter. The ceramic foam filter of the present invention has good high-temperature stability in the magnesium alloy melt, does not pollute the alloy, has good filtration and adsorption capacity for oxidation inclusions and flux inclusions in the magnesium alloy melt, and has a good filtration and purification effect and is heat-resistant. Small capacity, no need to preheat when using, small fluid resistance, large filtration capacity, through the filtration and purification test of metal magnesium and magnesium alloy melt, all performances are good.