In recent years, there has been an obvious reverse "mismatch" between copyright protection and content quality in domestic network video industry. The article constructs an endogenous copyright protection model with quality differentiation in a two-stage dynamic game.The research reveals that the reverse "mismatch" phenomenon in network video industry stems from the unequal legal status between large-sized and small-sized platforms. When there is a high nominal level of copyright protection, the unequal legal status implies differences in the actual strength of copyright protection between large-sized and small-sized platforms, leading to divergent copyright protedion decisions. This brings large platforms later market power and causes small platforms short-sighted effects. The quality crowding-out effect triggered by the former prompts large-sized platforms to choose low-quality content, while the latter forces small-sized platforms to opt high-quality content making good use of piracy "convenience". Therefore, while increasing the nominal strength of copyright protection, it is essential to focus on the fairness of copyright protection enforcement and promote high-level copyright protection across the entire industry, while maintaining content quality.