The choice between open and closed model strategies is one of the most strategically significant issues in the development of the large model industry, and a key factor in understanding the China-U.S. competition in artificial intelligence. Building on a clarification of the fundamental differences between “open weights” in the large model context and traditional open-source software, this paper systematically compares the advantages and limitations of the two strategies, and explains the underlying logic of strategy choice along four dimensions: technological position, profit-pool location, appropriability, and institutional environment. It then examines the development trends and strategy distribution of the Chinese and U.S. large model industries, with a focus on how strategy choice affects competition in the large model industry itself, competition in related upstream and downstream industries, China’s catch-up process, and the pattern of intelligent-technology diffusion and governance in both countries. The study finds that the United States has formed a pyramid structure dominated by frontier closed-source models, while China has formed a flying-geese structure dominated by open-weight models. Open-sourcing has enabled China to achieve asymmetric catch-up by trading diffusion for time and ecosystem for position, yet it also faces constraints such as a renewed widening of the frontier-model gap, the concentration of value in the compute segment where China remains dependent on others, and the reversibility of its ecosystem advantage. In line with the deployment of the 15th Five-Year Plan, China should make artificial intelligence a primary focus for cultivating future industries and new quality productive forces: maintaining diversified mechanisms for technological investment, coordinating the build-out of compute infrastructure with domestic substitution, consolidating its open-source ecosystem advantage, empowering the real economy and small and medium-sized enterprises through intelligent technologies, and deepening international cooperation and openness, so as to gain strategic initiative in both the China-U.S. AI competition and the broader science and technology industrial competition.