Abstract: To investigate the modification effect of the combined addition of Sr and La in ZL101 alloy, Sr and La elements were simultaneously added into the alloy to achieve the modification of eutectic Si phase and the refinement of α-Al grains. Optical microscopes, scanning electron microscopes and universal testing machine were used to systematically characterize the microstructure and mechanical properties of the alloy, so as to clarify the internal mechanism of the synergistic refinement and modification by Sr and La. The results show that after the combined addition of Sr and La, the eutectic Si changes from coarse lamellar or massive morphology to fine fibrous and granular morphology. At the same time, the secondary dendrite arms of α-Al are significantly refined. The addition of La can refine the α-Al and promote the spheroidization of eutectic Si phase. However, excessive addition of La will form coarse La-rich intermetallic compounds, reducing the tensile strength and elongation of the alloy. The ZL101 alloy with combined addition of 0.02%Sr and 0.3%La exhibits the best comprehensive mechanical properties. After heat treatment, its tensile strength reaches 292 MPa and the elongation is 7.2%.