The invention discloses a solid solution heat treatment method of Al-Zn-Mg-Cu alloy and aluminium alloy treated by using the same. The solid solution heat treatment method of the Al-Zn-Mg-Cu alloy comprises two stages of: (1) a low-temperature insulation precipitation stage: carrying out low-temperature insulation for 2 to 12h at 200 to 300 DEG C; and (2) a high-temperature short-time solid solution stage: carrying out solid solution for 15 to 30min at 470 to 485 DEG C. Compared with the conventional solid solution heat treatment, the composite solid solution heat treatment method of low-temperature insulation precipitation and high-temperature short-time solid solution can precipitate a great deal of second-phase grains from a shape-variation organization at the first step, effectively dissolves the second-phase grains at the subsequent second stage by pinning a subgrain boundary by utilizing grains precipitated at the lower temperature, and avoids subgrains from growing up and recrystallizing simultaneously. By adopting the treatments, the corrosion resistance and the strength of the alloy are improved simultaneously.