The　microstructure,　mechanical　properties　and　intergranular　corrosion　resistance　of　Al-Cu-Mn-Si-Mg-Er-Zr　alloy　with　squeeze　casting　in　the　peak　aging　state　at　different　temperatures　were　studied.　The　alloy　was　aged　at　165　°C,　175　°C　and　185　°C,　and　reached　peak　aging　at　18　h,　12　h　and　8　h　respectively,　among　them,　the　alloy　treated　with　175　°C/12　h　aging　has　the　highest　hardness,　reaching　149　HV,　and　the　yield　strength　is　also　the　highest,　which　is　387　MPa.　It　is　because　the　Q　phase　precipitated　during　the　aging　process　of　the　alloy　provides　a　heterogeneous　nucleation　site　for　the　θ′　phase,　the　average　size　of　the　θ′　phase　is　73.38　nm.　The　intergranular　corrosion　depth　of　the　alloy　after　aging　treatment　at　175　°C/12　h　was　the　deepest,　reaching　284.91μm.　At　this　time,　the　width　of　precipitation-free　zone(PFZ)　is　the　widest　in　the　grain　boundary　microstructure,　which　is　92.21　nm,　and　the　grain　boundary　precipitation　phase　is　continuously　distributed.　©　2024　IOP　Publishing　Ltd.