Evolutionary characteristics and implementation effects of China’s low-carbon policy system: a quantitative analysis based on policy texts

China’s low-carbon policy system is a key institutional arrangement for advancing carbon disclosure, promoting green transformation, and supporting the achievement of the “dual-carbon”goals. However, existing studies have paid limited attention to the policy system itself as an integrated and evolving object of analysis. To address this gap, this paper develops a three-dimensional analytical framework of policy instruments, policy objectives, and policy effectiveness, and applies content analysis and temporal interval analysis to 1008 coded policy documents issued between 2007 and 2024. The results show that first, policy instruments are structurally imbalanced, with environment-type instruments dominating the policy mix, while supply-side and demand-side instruments remain relatively insufficient. Second, policy objectives are primarily oriented toward the national “dual-carbon”strategy, with comparatively limited attention to corporate sustainable development and investors’ low-carbon information needs. Third, policy effectiveness is unevenly distributed, as most policy texts are concentrated in provincial-level guiding documents, whereas high-authority policy documents remain limited. Fourth, China’s low-carbon policy system exhibits a clear three-stage evolution, moving from initial exploration to system construction and deepening, and then to adaptation and innovation. Finally, broader trend-based evidence suggests that changes in carbon emissions, green finance, and firm-level green transformation are broadly aligned with the direction of China’s low-carbon policy development. By shifting the analytical focus from isolated policy measures to the policy system itself, this study provides a more systematic basis for understanding the internal logic and evolutionary dynamics of China’s low-carbon governance, while also offering policy implications for China and institutional reference for other developing countries.