The effect of V alloying on the solidification process, microstructure, and mechanical properties of an Al-9Si alloy was investigated. The results show that when V is added to the Al-9Si alloy, the Si2V phase precipitates, but no AlV phase precipitates, and V has no obvious effect on the precipitation temperature of the primary α-Al. With increasing V content, the nucleation temperature and supercooling of the primary α-Al particles in the Al-9Si alloy increase simultaneously. By adding 0.4 wt. % V, the nucleation increases from 607.5 ℃ for Al-9Si to 612.6 ℃ , and the supercooling increases from 24 ℃ to 27.1 ℃. With increasing V content, the nucleation temperature slightly increases, but the nucleation supercooling slightly decreases. A transition from columnar to equiaxed growth occurs when V is added to the Al-9Si alloy. The α-Al grain size of the Al-9Si-0.4V alloy is refined from 593 μm for Al-9Si to 302 μm. V has no modifying effect on the eutectic Si, but V could cause the transformation of needle-shaped β-Al5FeSi to fishbone-shaped Al12 (Fe,V)3Si. The tensile strength, yield strength and elongation of the 0.6 wt. % Sb -modified Al-9Si-0.4V alloy are 153.9 MPa, 78.5 MPa and 6.56%, respectively, which are 23.8%, 14.1% and 102.4% greater than those of the Al-9Si alloy. The hardness increases from 47.3 HV to 59.1 HV. The fracture morphology of the Al-9Si alloy is composed of tearing edges and cleavage steps, while the cleavage steps of the Al-9Si-0.4V-0.6Sb alloy are significantly reduced, the tearing edges become denser, and dimples with eutectic Si as the center appear, revealing mixed fracture features.