The horizontal continuous casting process with the heated mold has been applied to study the effect of grain refiner or modifier such as Ti or Sr, respectively, in Al-11.3wt%Si alloy. The results represented that the addition of 0.02%Sr or 0.2∼0.4%Ti promoted the directionality of primary α dendrite, whereas the addition of 0.6%Ti suppressed the directionality. Also, the addition of 0.02%Sr suppressed the occurrence of feathery grains, while the addition of 0.2%Ti promoted the occurrence of feathery grain. The addition of Ti over 0.4% suppressed the occurrence of feathery grain, resulting from the in creasing grain-refining effect. The addition of Ti also increased the coarsening effect of eutectic silicon phase in Al-11.3%Si alloy.