Abstract: To achieve high-quality and high-efficiency additive manufacturing of large metal components, a multi-arc additive manufacturing head device and control system was first designed and developed, integrating multi-arc additive units,three-dimensional measurement units, subtractive machining units, and a central control unit into a comprehensive multi-arc additive manufacturing system. Subsequently, the coordinated motion patterns of arc welding torches during multi-arc additive manufacturing were analyzed, revealing that when the forward speed of the welding torch V_Y, the spacing L between contour arc welding torches 1 and 2, and the oscillation speed V_X satisfy the relationship V_Y/V_X=7/L, a well-fused deposited layer can be achieved. Finally, using the flatness of the multi-arc deposited layer as an indicator, a quadratic regression general rotational combination experiment was designed to analyze the influence of individual process parameters on the flatness of the deposited layer. The results indicate that the order of influence on the flatness is: contour arc current, filler arc current,deposition layer width, and oscillation speed of the filler arc welding torch. Additionally, the optimal process window for multi-arc additive manufacturing is determined:contour arc current of 70-90 A, filler arc current of 580-620 A, deposition layer width of 80-130 mm, and the oscillation speed of the filler arc welding torch of 12-14 mm/s.