Abstract: Different melting processes have a great influence on the effect of alloy refinement and densification. The effect of melting process on the microstructure and mechanical properties of A356 alloy after refinement and densification was investigated by using OM, SEM and tensile testing machine to explore a melting process for A356 alloy after refinement and densification. The results show that the cooling rate has a large influence on the effect of Al-Sr-Y refining agent, when the cooling rate is less than 3.5 K/s, the effect of Al-Sr-Y refining agent can not be fully developed, there are more needle-like and massive eutectic Si in the structure, and the α-Al dendrites are coarse at this time. When the cooling rate is 3.5 K/s, almost all eutectic Si is transformed into fine fibers, and the α-Al dendrites are significantly refined. The best refining and densification temperature of A356-0.3wt% Al-Sr-Y alloy is about 735 ℃, when the temperature exceeds 735 ℃, the oxidation burn loss of Al-Sr-Y refining and densification agent gradually increases, resulting in the decrease of its refining and densification capacity.