Phase-selective recrystallization in Al-Si alloys is based on the principle of strain distribution to achieve recrystallization of the soft phase and recovery of the hard phase, thereby spheroidizing the silicon phase and refining the aluminium phase. After phase-selective recrystallization treatment, the alloy exhibits a high work hardening rate and elongation. Solid solution treatment, which interacts with phase-selective recrystallization, is an important step in strengthening and toughening aluminium alloys. On the one hand, the initial structure has a certain influence on the strain distribution of phase-selective recrystallization; on the other hand, the solid solution process of aluminium alloys can affect the precipitation strengthening effect. Therefore, the influence of the morphology of the eutectic silicon phase on phase-selective recrystallization during the solid solution process of a cast Al-7Si-0.65Mg alloy was explored in combination with aging precipitation to increase the alloy strength and toughness. The results show that a 0.5 h short solid solution treatment can maintain a clear and non-dispersed framework structure of eutectic silicon particles in phase-selective recrystallized alloys, while increasing the Si and Mg contents in the matrix promotes the precipitation of the Mg2 Si strengthening phase, resulting in a yield strength of 300 MPa and an elongation after fracture of 9.5% , which is significantly better than that of the traditional T6 state.