The effect of Cu content on the microstructure， fracture and hardenbility of Al-7.6Zn-1.6Mg-XCu alloy was investigated by means of mechanical tensile and jominy end quench testing combined with optical microscopy（OM），scanning electron microscopy（SEM） and transmission electron microscopy（TEM）. The results showed that the strength of the alloys increased first and then decreased with the increase of Cu mass fraction， and the strength of the alloy peaked at Cu mass fraction of 1.70 %. The anisotropic mechanical properties of the alloys decreased first and then increased with the increase of Cu mass fraction， and the alloys had the minimum anisotropy when the Cu mass fraction was 1.45 %. Concomitant with the increase of Cu mass fraction， a transition in fracture mode was observed from predominantly transgranular dimpled rupture to predominantly intergranular dimpled rupture. Compared with the change of the longitudinal elongation of the alloys， the Cu mass fraction had a significant effect on the transverse elongation of the alloys. With the increase of Cu mass fraction and the decrease of quenching rate， obvious precipitation free zone（PFZ） was observed around the equilibrium phases of the alloys after aging， which resulted in significant reduction in hardenability and hardness of the alloys.