Abstract: The Al-Mg-Zn-Cu-Sc alloy was fabricated via dual-wire arc additive manufacturing to improve the processing and defect problem. According to the process stability and forming conditions and microstructure, the process parameters such as wire feeding position, wire feeding speed, and variable polarity frequency were studied. The parameters with less porosity and better forming conditions were obtained. The microstructure and mechanical properties of Al-Mg-Zn-Cu-Sc alloy prepared at different scanning speeds were analyzed. The microstructure and failure zone of the sample were observed, and the fracture types and microstructure characteristics were confirmed. Finally, the process range of Al-Mg-Zn-Cu-Sc aluminum alloy prepared by dual-wire arc additive manufacturing was obtained, and the basic microstructure characteristics of deposited Al-Mg-Zn-Cu-Sc aluminum alloy were defined.