In order to comprehensively weigh the mutual constraints and design contradictions of ultra-long blades in transportation logistics, aerodynamic efficiency, structural topology, lightweight demand and service life, this paper focuses on the key technical bottlenecks and design difficulties in the research and development of large megawatt blades, systematically discusses the structural design methods of adaptive blades, bionic blades and segmented blades, and further expounds the aerodynamic shape design for power maximization and the design concept of recyclable materials for sustainable development. The research results can provide theoretical basis and technical reference for solving the key problems of large-scale blades in development, transportation, noise reduction, operation and maintenance, improving their life cycle performance, realizing cascade utilization and green recycling, and promoting the application of new intelligent materials, bio-based materials and biodegradable materials, and have guiding significance for realizing cost reduction and efficiency increase.