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The effect of B addition on the morphology of iron-rich phase in Al-Si alloy with ?1.0% Fe and ?1.0% Mn was invesitigated with optical microscopy, SEM, EDS and DSC. The obtained results show that an appropriate amount of B addition results in not only an obvious refinement on Al-Si alloy grain, but also the morphology, size and volume fraction of the iron-rich phases. With 3% Al-3B addition, the volume fraction and mean size of the iron-rich phases were reduced to 4.13% and 7.5 μm, respectively. With the increase of Al-3B addition within 3%, the formation of coarse primary iron-rich phase has been suppressed, and the primary coarse iron phase, large size dendritic iron-rich phase and netlike iron-rich phase are transformed into small size and high density of dendritic, chinese script shaped and granular. However, excessive Al-3B addition leads to the formation of polygon primary iron rich phase and refined grain size and iron-rich phase.