The effects of Sr modification on the microstructure and properties of Al₃Ti/ADC12 composite were systematically investigated. The microstructures and fracture surfaces of composites were examined by optical microscope and SEM. Results showed that the addition of Sr reduced the sizes of the α-Al primary phase and Al₃Ti particles and modified the morphology of composites. The optimum level of added Sr content was 0.25 wt%, and the eutectic silicon changed from a acicular or short rod shape into a granule one. Coarse dendritics of the primary α-A1 phases were fully refined. Results also showed that Sr addition led to the improvement inSmechanical properties. Compared with matrix alloys, the tensile strength and elongation of the composite were increased by 36.9% and 58% when the Sr addition was 0.25 wt.%. Furthermore, fractographic examinations revealed that cleavage surfaces and brittle plain area could hardly be seen from the Al₃Ti/ADC12 composite with addition of 0.25wt.% Sr. The dimples were increased in quantity and diminished in size, deeper and well-distributed. The fracture appearances matched the tendency of the tensile properties.