ZL114A alloy is a casting hypoeutectic Al-Si alloy independently developed by Beijing Institute of Aeronautical Materials. The porosity, distribution and morphology of micro-pores have a great influence on the mechanical properties of the alloy. Using density measuring instrument, SEM with EDX, the effects of Y element on the porosity, distribution and morphology of micro-pores of ZL114A ingot were studied in sand casting conditions. The results showed that with the addition of Y，because the Y atomic number is larger，the theoretical density and actual density of ZL114A alloy increased slightly. At the same time，the porosity of the alloy decreased, and the distribution of micro-pores changed from being distributed throughout the alloy matrix to being more distributed in the eutectic region, and the morphology changed from coexistence of particles and networks to network-based ones. Although the Y element had an effect on the porosity, distribution and morphology of micro-pores, the Y element did not play a role by directly interacting with gases in the alloy melt.