The wear resistance of Hyper-eutectic Al-Si alloy, have recently been noticed as a new automobile material, was investigated. For the purpose of developing wear resistant Al-Si alloy, some factors which attribute to wear resistance are examined as follows; refinement of primary Si particle during solidification, and effect of refinement on wear resistance and other mechanical properties. The most effective refinement was accomplished by adding both NaF and S, and this improve wear-resistance in abrasive wear type. The wear losses of specimens cast in metal mold were ruduced to 80% of those in sand mold. T6 heat treatment increases hardness, which resulted in reduction of wear loss about 3∼18 %.