Composite materials are one of the important factors to establish the competitive advantage of large commercial aircraft industry in China. Firstly, this paper sorts out the upstream, midstream, and downstream segments of the composites industry for large commercial aircraft. Subsequently, competitiveness of composites industry for large commercial aircraft in China was analyzed based on Diamond Model from six dimensions, including: (1) the advantages and disadvantages of production factors such as capital, software and hardware, and talent team; (2) the huge market demand of civil aviation transportation industry and large commercial aircraft industry in China; (3) the sound and rapid development of large commercial aircraft industry chain in China; (4) the resource integration of domestic OEMs and the strategic measures of foreign OEMs; (5) national and local policy support; (6) large commercial aircraft composite application and industrial development opportunities. Finally, based on the analysis of the diamond model, relevant government, customer, industry, university, and research policy recommendations for the development of composites industry for large commercial aircraft in China were put forward. The Diamond Model can provide guidance for the formulation of large commercial aircraft industry planning and the decision-making of related R&D enterprises in China.