To achieve high-performance precision forming and low-cost manufacturing of heat-treatable aluminum alloy spun parts, this paper proposes a new process route: die-less spinning of pre-flanged blanks followed by solution treatment, die spinning and aging. Through a combined approach of numerical simulation and experimental validation, the influence of pre-flanged structures on the forming accuracy of conical parts in die-less spinning and subsequent die spinning formability was systematically investigated. The results demonstrate that compared with non-flanged blanks, pre-flanged structures can effectively enhance the forming accuracy of conical parts in die-less spinning, with larger flanging angles yielding greater improvements. Furthermore, the final spun conical parts obtained from the new process route exhibit superior contour accuracy and tensile strength. These findings provide technical support for the low-cost, high-performance manufacturing of large-scale heat-treatable aluminum alloy thin-walled structures.