High-temperature and short-time (HTST) solution heat treatment combined with non-isothermal aging (NIA) was employed to regulate the microstructure and properties of Al-4.5Mg-2.0Zn-0.3Ag alloy. Results indicate that HTST solution heat treatment can not only retain partial deformation dislocations, but inhibit the recrystallization behavior and increase the proportion of low-angle grain boundaries (LAGBs). In the subsequent NIA process, HTST solution heat treatment combined with NIA is instrumental in restraining the degradation of dislocations and promoting precipitation of nano-scale T''''-Mg₃₂(Al,Zn,Ag)₄₉ phase, which improves the strength of the alloy greatly. In addition, a higher fraction of LAGBs and the discontinuous distribution of grain boundary precipitates caused by this novel technology meliorate the corrosion resistance of Al-4.5Mg-2.0Zn-0.3Ag alloy.