Against the backdrop of Chinese-style modernization, promoting high-quality development has become a key strategic goal for achieving economic and social transformation. Policy documents, as a concrete embodiment of top-level design and an implementation tool, play a crucial role in guiding practice and fostering innovative development. This paper takes the high-quality development policy documents issued by the central government and the three provinces and one city in the Yangtze River Delta as research objects. Based on the theoretical framework of “policy actors—policy agendas—policy quality”, and employing text co-occurrence network analysis and the PMC index model, this study systematically evaluates the hierarchical characteristics, agenda structure, and text quality of high-quality development policies in the Yangtze River Delta. The findings indicate that central-level policies provide strategic guidance and institutional framework for high-quality development in the Yangtze River Delta, while the policies of the three provinces and one city focus on specialized implementation in specific areas, forming a hierarchical pattern that combines strategic deployment with specialized execution.In terms of policy issues, a radial network structure has formed, with five key sub-issues effectively supporting the region’s development goals. From the perspective of policy quality, the policy text quality in the Yangtze River Delta has reached an “acceptable” level. Given its demonstrative role in the process of Chinese-style modernization, it is recommended to further enhance the coordination of policy issues, optimize the policy framework, and improve the comprehensiveness and specificity of policy implementation to support the long-term goals of high-quality development in the region and nationwide.