The invention discloses an aluminum alloy having high abrasion resistance, a spherical cap made of the aluminum alloy, and a preparation method of the spherical cap. The aluminum alloy comprises the following components of, by mass fraction, 0.10-0.40% of Mn, 2.30-3.30% of Mg, 0.15-0.25% of Cr, 3.50-4.50% of Zn, 0.15% of Cu, less than or equal to 0.30% of Si, less than or equal to 0.40% of Fe, 0.15% of subgroup elements and the balance Al. The abrasion resistance and the corrosion resistance of an aluminum alloy spherical cap body are improved substantially; a series of problems such as high surface roughness are solved; a surface layer of the spherical cap subjected to rolling treatment, mechanical polishing and surface hard anodic oxidation treatment is a mirror surface, the surface hardness is raised to 300-500 HV, the surface roughness is not greater than 0.8 micrometer, the core hardness of a spherical cap component is 172-185 HB, the yield strength is 270-470 Mpa, the strength ofextension is 300-560 Mpa, the elongation percentage is 8-9%, and the wear rate is 3.4*10<-5> to 4.1*10<-5> mm/m under the conditions that the load is 10N and the speed is 10000 r/min; and the usability, the fatigue resistance and the strength of the spherical cap are improved obviously.