The influence of Y content on the microstructure, mechanical properties, and corrosion resistance of as-cast Mg-2.0Zn-0.3Mn-2.0Al-xY (0≤x≤5.0wt%) alloys melted in a ZGJL0.01-40-4 medium-frequency induction furnace at 800±5 ℃ was investigated. The results indicate that the second phases in the Y-containing alloys are mainly composed of Al₂Y and (Al, Zn)₁₁Y₃ phases. With the increase in Y content, the grain size of alloy is gradually decreased, while the content and size of the second phases are gradually increased. The mechanical properties and corrosion resistance show a trend of firstly increasing and then decreasing. When the Y content is 3.0wt%, the alloy exhibits good mechanical properties and corrosion resistance due to the coupled effects of grain size and type, size, and distribution of the second phase. Its ultimate tensile strength, yield strength, and elongation are 210.47±2.26 MPa, 132.71±2.28 MPa, and (16.56±1.11)%, respectively. The average mass loss corrosion rate and hydrogen evolution corrosion rate are 4.87±0.30 and 4.69±0.31 mm/a, respectively.