Abstract: Al-Zn-Mg alloys are widely used in rail vehicles due to their high specific strength and excellent mechanical properties. This paper investigated the effect of different temperature parameters on the hardness and mechanical properties of Al-4.5Zn-1.3Mg alloy after regression reheat treatment. It is found that, when the regression time is 105 min at 185 ℃, Al-4.5Zn-1.3Mg alloy can achieve excellent mechanical properties, such as a tensile strength of approximately 408 MPa and an elongation of about 15%. Through regression heat treatment, Al-4.5Zn-1.3Mg alloy can not only retain sufficient GP zones to avoid excessive dissolution, and promote the precipitation and coarsening of η' phases during re-aging processes, but also the precipitated phases at grain boundaries are discontinuously distributed and form a precipitate-free zone (PFZ) of suitable width, which improves the plasticity of aluminum alloy. Therefore, reasonably controlling the regression temperature can achieve good strength and plasticity of Al-4.5Zn-1.3Mg alloys.