Abstract The effects of Al content on the microstructures and the mechanic properties of complex brass (Cu-22.7Zn-Al-1.0Ni) in as-cast, hot-rolled and cold rolled strip were investigated. The results show that Al is able to significantly reduce the size of α phase and increase the area of β-phase. With the increase of Al content, α phase transforms from block to strip shape and distributes more uniform, and the tensile strength and hardness is improved, however, the elongation is decreased. With the addition of 3.0% Al in the alloy, the hardness and tensile strength of cold-rolled plate with the thickness of 0.2mm can reach up to the peak, 255HV and 820MPa. The proper deformation processing and heat treatment will induce that the hardness and tensile strength of 0.2mm thick cold-rolled plate are 20.3% and 7.9% than that of 0.4mm thick cold-rolled plate, respectively.