High-alumina magnesium alloy

The invention relates to a high aluminum-magnesium alloy and the weight percentages of the components are as follows: 10.5 to 11.5 percent of Al, 0.17 to 0.40 percent of Mn, 0.45 to 0.90 percent of Zn, less than or equal to 0.08 percent of Si, less than or equal to 0.004 percent of Fe, less than or equal to 0.025 percent of Cu, less than or equal to 0.001 percent of Ni, 0 to 0.0015 percent of Be and the allowance is Mg. Compared with the existing AZ91D magnesium alloy, the invention has the advantages of improving the fluidity and at the same time decreasing the melting points of the alloy and then relatively reducing the cost.