Abstract: The cross-border and spillover characteristics of natural disasters make the demand for cross-regional joint prevention and control of natural disasters increasingly prominent. The inter-regional emergency management policy coordination system has become the key to reducing vertical coordination costs and balancing regional and local contradictions.However, the existing research mostly focuses on the measurement of the results of inter-regional policy coordination, and pay little attention to how the inter-regional policy coordination system can achieve a balance between regional common action and local differentiated risk response. To this end, by constructing a “structure-function” cross-regional emergency management policy collaborative analysis framework, using LDA topic model, TF-IDF weight analysis and social network analysis methods, the collaborative structure of the regional natural disaster policy coordination system in the Yangtze River Delta is analyzed. Combined with the case of the Yangtze River Delta’s joint response to typhoon “MeiHua”, the balanced role of the regional policy coordination system in promoting joint prevention and control of natural disasters is analyzed. The study found that an effective inter-regional policy coordination system constitutes a “harmony in diversity” framework, balancing unified regional action with space for local adaptive response. Under this structure, the policy objectives play a guiding role in strategic decision-making, balancing the regional requirements of joint prevention and control and the local demands of territorial risk response; policy tools play a complementary role in promoting emergency response capabilities, linking regional collaborative standards and local tool preferences; the policy relationship plays the role of organizational relationship building, ensuring that the regional power and responsibility boundary is clear and the local action subject is scientific, and the three jointly promote the coordinated development of cross-regional natural disaster joint prevention and control. The above findings extend the interpretation chain of policy coordination theory at the “role play” level, and also provide practical paths and policy design principles for promoting the coordinated development of cross-regional emergency management.