With the rapid development and increasing installed capacity of offshore wind power, the market demand for large main wind power shafts has increased sharply, necessitating urgent requirements for the research and development of high-performance main shaft materials and advanced manufacturing processes. Focusing on the main shaft structure and usage requirements of large offshore wind turbines, innovative research has been conducted from three aspects: casting material, key casting technology, and machining technology. In terms of materials, by optimizing the chemical composition and innovating nodulizing and inoculation processes, high-performance solid solutions strengthened with as-cast ferritic ductile iron have been obtained, meeting the stringent requirements of the main shaft for high strength, high toughness, and low-temperature impact resistance. The integration of the casting process with self-feeding technology has improved the process yield and significantly decreased the product scrap rate. The use of vertical multihead CNC machine tools and optimized machining processes has improved machining accuracy and production efficiency. This main shaft production technology reduces production costs and has been put into large-volume industrial production, improving the overall production yield and economic benefits.