To address the high-quality manufacturing demand for multi-functional integrated exterior enclosure components in ultra-low energy consumption buildings, this study focuses on the key technical challenges in the lean manufacturing of large-scale lightweight ultra-high performance concrete (UHPC) ribbed wall panels. Starting from the structural and performance requirements of such wall panels, a high-performance steel fiber-reinforced UHPC mixture was developed, and a complete lean manufacturing system integrating three core processes was established, including right-side-up ribbed formwork, high-precision casting molding, and high-temperature low-humidity steam curing. The research results indicate that this technical system can effectively control the shrinkage, warpage deformation, and surface discoloration of large-scale lightweight UHPC ribbed wall panels, successfully improving the product quality and production efficiency of these novel exterior wall panels and achieving the goal of lean manufacturing. This study provides technical support and practical examples for advancing the high-level manufacturing of exterior enclosure components in ultra-low energy prefabricated buildings.