The invention relates to a magnesium aluminate spinel foamed ceramic filter which is excellent in high-temperature chemical stability and thermal shock resistance. A preparation method of the magnesium aluminate spinel foamed ceramic filter comprises the following steps: firstly, using water-base resin, a dispersing agent and water as a solvent, forming ceramic powder by using magnesium aluminate spinel powder, aluminum oxide powder and magnesium hydroxide powder, and mechanically stirring to prepare slurry; soaking polyurethane porous sponge serving as a carrier in slurry, pressing to remove excessive slurry to prepare a preform body, drying and sintering to obtain the magnesium aluminate spinel foamed ceramic filter. The foamed ceramic filter disclosed by the invention can satisfy rigorous requirements of filtering of molten magnesium alloy, has good high-temperature stability, does not pollute the alloy, has good filtering and adsorbing effect on inorganic impurities in the molten magnesium alloy, and is good in filtering and purifying effect, small in fluid resistance, and large in filtration yield; and good using effect is obtained through trial in casting production of metal magnesium and magnesium alloy.