Policy instruments in China’s marine environmental governance: an administrative law perspective on structural configuration, operational challenges, and optimization pathways

China employs a diverse mix of marine environmental governance instruments to address complex marine environmental risks. Existing studies have primarily examined these instruments through public-policy typologies or focused on particular legal institutions, leaving their underlying administrative-law logics insufficiently explored. This study develops an administrative law-based framework drawing on red-, green-, and amber-light theories to examine the configuration of policy instruments in China’s marine environmental governance. Based on content analysis of 34 currently effective national-level policy documents, supplemented by normative legal analysis, the study identifies the relative prominence and internal structure of different governance instruments. The findings reveal a strongly red-light-oriented configuration. Red-light instruments account for 83.4% of coded references, while green-light and amber-light instruments account for 7.3% and 9.3%, respectively. Within the red-light category, ex post regulation accounts for 52.6% of coded references, exceeding ex ante prevention and process-oriented regulation. Green-light instruments are concentrated in fiscal support, whereas cost-internalization, risk-sharing, and professional environmental service mechanisms remain less prominent. Amber-light instruments are centered on information disclosure, while substantive public participation and expert consultation receive comparatively limited attention. The study argues that the predominance of red-light instruments is institutionally justified by the externalities, cumulative pressures, and potentially irreversible consequences associated with marine environmental risks. The central challenge lies in the internal configuration and functional coordination of the instrument mix. China’s marine environmental governance should therefore strengthen prevention-first and risk-oriented red-light regulation, develop conditional fiscal support and diversified responsibility sharing, and move amber-light instruments from disclosure-centered transparency toward substantive participation and administrative accountability. By combining policy-text content analysis with normative administrative law analysis, this study offers an administrative law-based perspective for assessing the legality and effectiveness of marine environmental governance. It also provides theoretical reference and practical implications for the broader study of government regulation.