The invention relates to an aluminum alloy sacrificial anode suitable for sea mud in the Bohai Sea Gulf. The aluminum alloy sacrificial anode is compounded from nine elements and comprises the following components in percentage by weight: 2.0-5.5 percent of Zinc, 0.01-0.05 percent of indium, 0.01-0.08 percent of tin, 4-8 percent of magnesium, 0.12-0.32 percent of lanthanum, 0.12-0.32 percent of actinium, 0.03-0.04 percent of cerium, less than or equal to 0.05 percent of silicon serving as an impurity element and the balance of aluminum. Most of added lanthanum, actinium and cerium elements exist in a phase segregation state, are mainly centralized on grain boundaries, are also distributed in crystals, are used for forming binary or polynary compounds such as aluminum-rich rare-earth phases such as LaAl4, CeAl4 and the like, and are used for forming intermetallic compounds with aluminum. The aluminum alloy sacrificial anode is suitable for sacrificial anode protection of the sea mud environment of the Bohai Sea Gulf, and has high adaptability to sea mud with high porosity ratio, large temperature range change and high corrosion, the characteristics of high current efficiency and long service life and the advantages of good protecting effect, long service life, saving in anode materials and the like.