In this paper, the addition of Er element in the alloy of Al10Si1.5Fe2.25Co was carried out to study the effect of different mass fractions of Er on the refinement and mechanical properties of the microstructure. The research shows that the cerium element can effectively refine the eutectic silicon structure in the high-iron aluminum-silicon alloy after Co metamorphism. When the addition amount of element Er is 0.5wt.%, the eutectic silicon has the best refining effect; At the same time, α-Al also obtained a certain refinement, and excessive Er will lead to the precipitation of acicular Al3Er phase, but the element Er has no obvious refinement effect on the bulk iron-rich phase. With the refinement of eutectic silicon, the plasticity of the alloy is enhanced and the tensile strength is also improved. When the Er content is 0.5%, the maximum tensile strength is 160.8 MPa and the elongation after fracture is 1.89%. The alloy was increased by 5% and 19.6% compared to the alloy without Er added, and the excess of Er resulted in a decrease in strength and ductility. At the same time, with the increase of Er content in the alloy, the wear rate and friction coefficient of the alloy increased. When Er content is 0.5wt%, the relative wear resistance of the alloy reaches the best.