Abstract: The effects of adding different contents of Sr and Y on the microstructure and mechanical properties of A356 aluminum alloy were studied by using XRD, metallographic microscope, scanning electron microscope and mechanical properties test.The results show that when adding 0.04%Sr and 0.3%Y into the alloy, the equivalent diameter of α-Al grains and the value of secondary dendrite spacing tend to be stable.The tensile strength and elongation reach the maximum at this time, which are 188.3MPa and 7.2%, respectively.