Al-Zn-Mg-Cu-Zr-Ti and Al-Zn-Mg-Cu-Zr-Ti-Cr alloys were prepared by cast metallurgy. The effects of Zr, Ti and Cr additions on the microstructure and properties of Al-Zn-Mg-Cu alloy were compared to those of Zr and Ti additions by optical microscopy, scanning electron microscopy, transmission electron microscopy, hardness, tensile test and corrosion resistance measurement. The results show that the combined additions of Zr, Ti and Cr to Al-Zn-Mg-Cu alloys lead to the formation of L12-structured Zn, Mg, Cu-containing (Al, Cr)3(Zr, Ti). These 10-20 nm dispersoids remarkably pin the dislocations and subgrain boundaries. Compared to the combined additions of Zr and Ti, the combined additions of Zr, Ti and Cr to Al-Zn-Mg-Cu alloys have stronger grain refinement and recrystallization inhibition effect. Moreover, combined additions of Zr, Ti and Cr can enhance the resistance to stress corrosion cracking and exfoliation corrosion with the improved strength, fracture toughness and ductility. The critical stress intensity (KISCC) is enhanced from 5.0 MPa·m1/2 to 12.6 MPa·m1/2 and exfoliation corrosion from EC to EB-. © 2016, Central South University of Technology. All right reserved.