This paper describes the effect of cooling rate on grain size, SDAS and thermal characterization results of cast AC AlSi 7 Cu 2 alloy. The solidification process was studied from the cooling curve and crystallization curve at solidification rates from 0.16 to 0.71°C∙s -1 . It was found that the nucleation temperature of aluminum dendrites and the proportion of solid at the coherence point of dendrites increased with increasing solidification rate, indicating an increase in mass feeding. In addition, it was observed that the non-equilibrium solidus temperature and grain size of the constituent grains of the SDAS decreased with increasing solidification rate.