Abstract:The effects of retrogression and re-aging heat treatment on the microstructures, mechanical properties and stress corrosion sensitivity of Al-5.8Zn-2.7Mg-1.6Cu aluminum alloy have been investigated.This paper uses orthogonal test methods to explore. The results show that: after retrogression and re-aging heat treatment, the grains are elongated and fibrous, and the second phase is distributed in the crystal and grain boundaries,distributed along the rolling direction. The mechanical properties, electrical conductivity and stress corrosion resistance of Al-5.8Zn-2.7Mg-1.6Cu aluminium alloy can be significantly improved by retrogression and re-aging heat treatment. By analyzing the results, the following conclusions can be drawn:tthe pre-aging time and retrogression temperature are the most important factors affecting the performance of Al-5.8Zn-2.7Mg-1.6Cu aluminum alloy; If the retrogression temperature is lower and the retrogression time is extended, it is more conducive to the discontinuous precipitation of the strengthening phase at the grain boundaries; if the retrogression temperature is higher and the retrogression time is shorter, the precipitation in the crystal is smaller, and the precipitation phase is coarser at grain boundaries; The preferred heat treatment process for Al-5.8Zn-2.7Mg-1.6Cu aluminum alloy is: 450℃×120min+470℃×40min+120℃×24h+185℃×1h+120℃×18h。