Abstract: A certain batch of ZL101A aluminum alloy samples showed shrinkage porosity defects on the fracture surface after tensile testing. The cause of shrinkage porosity defects and the relationship between defects and material mechanical properties were analyzed using methods such as macroscopic observation, X－ray detection, metallographic examination, scanning electron microscopy and energy spectrum analysis, mechanical property testing. The results show that ZL101A aluminum alloy did not receive timely local shrinkage during the casting process, resulting in inconsistent shrinkage of the molten metal during solidification, leading to shrinkage porosity defects in the material. The shrinkage porosity defect seriously reduced the mechanical properties of ZL101A aluminum alloy material. With the increase of shrinkage porosity defect area, the tensile strength and elongation after fracture of the material showed a downward trend.