Abstract: Collaborative governance of the regional ecological environment is an important path to accelerate regional green transformation and promote harmonious coexistence between humans and nature between regions, which is the internal logic and requirement of ecological green integration construction in the Yangtze River Delta.Based on discussing the current situation of ecological environment governance in the Yangtze River Delta region, we elaborated on the institutional difficulties faced by ecological governance, such as incomplete top-level design mechanisms, unsmooth interest coordination mechanisms, unclear rights and responsibilities of governance entities, and incomplete joint prevention and control mechanisms.Based on the characteristics of collaborative governance theory and regional ecological environment governance, an optimization path was proposed to optimize the top-level decision-making design mechanism, streamline the interest coordination mechanism, improve the participation mechanism of multiple stakeholders, and improve the joint prevention and control mechanism.It has important theoretical values for improving the ability of cross regional ecological environment co-protection and joint governance, and promoting the construction of ecological green integration in the Yangtze River Delta.