The invention discloses a formula for casting aluminum alloy hubs. The formula is prepared from, by weight, 6.5-7.5% of Si, 0.28-0.45% of Mg, 0-0.12% of Fe, 0-0.02% of Cu, 0.02-0.05% of Mn, 0.04-0.05% of Zn, 0.10-0.20% of Ti, 0.2-0.6% of Sr, 0.01-0.05% of Cr, 0.01-0.02% of Zr, 0.025-0.05% of B, 0.4-0.8% of mixed light rare earth and the balance Al. Due to the fact that Sr and the mixed rare earth metal serve as an alterant together, the surface defects of alloy phases can be overcome, surface tension on a new-phase interface and an old-phase interface is reduced, and the problem that compactness is reduced when only Sr is added is avoided. Zr, Ti, Cr and Al work together, the cast structure is further refined, and the hardness and the toughness of aluminum alloy are improved.