China has witnessed a road for effective environmental governance, providing a great opportunity for understanding the Chinese institutional advantage. Based on the Central Environmental Inspection(CEI), this paper adopted an institutional complementarity perspective to explore how China is getting its institutions right in environmental governance. Results show that the design and implementation of CEI can compensate the disadvantage of laws and other institutions, and the CEI mechanism itself exhibits internal complementarity, that is, structural complementarity between politics and rule of law, functional coupling between party regulation, policy and the law, combination between vertical inspection and comprehensive supervision, and the healthy interaction between party and the state, the government and society. The formation mechanisms of institutional complementarity include the construction of history and context, changing beliefs of the party, state-level institutional experiments and learning-by-doing mechanisms.The conclusion implies that China can not only achieve economic success by hierarchical local experiments, but also manage to solve environmental problems by institutional experiments led by the state.