Excellent mechanical properties and satisfactory corrosion resistance were achieved in an Al–Zn–Mg–Cu alloy via non-isothermal ageing (NIA) treatment. The precipitation and age-strengthening were elucidated by combining the TEM observing, DSC analysis and the mechanical properties testing results. The corrosion resistance was evaluated based on the measured electrical conductivity. The effect of staring temperature (T_s) and the cooling rate (R_c) of the NIA processes on the properties was systematically investigated. The continuously decreasing temperature is found inhibit existing precipitates’ coarsening and also induces secondary precipitation. High T_s and low R_c bring about high conductivity and low hardness. Extra hardening together with a conductivity decrease occurs at the later stage of NIA processes due to the forming of fine secondary precipitates. High strength combined with high conductivity can be obtained by setting T_s at the 180–190 °C range and R_c at the 10–20 °C/h range. An optimized NIA process (cooled from 190 to 100 °C at 20 °C/h) provides higher strength and comparable SCC resistance within a halved processing time by looking the typical T74 ageing as a reference.