Recently, a new super-high-strength Al-Zn-Mg-Cu alloy with Zr bearing was developed in BIAM. In this paper, the effect of microalloying element Zr on the microstructure and mechanical properties of the alloy was investigated. It was found that the influence of Zr on the microstructure and age-hardening behaviors was remarkable. The strength of the alloy increases with increasing the content of zirconium, and the peak value of the elongation appeared when the content of Zr was 0.06%(mass fraction) and then decreases. The fracture behavior was also studied. The result shows that the fracture mechanism of the alloy was converted from intergranular brittle to transgranular ductile model with increasing the content of zirconium. Finally, the optimum contents of Zr in the alloy were proposed as 0.10%~0.14%.