As the world's highest level of regional integration, the European Union has a unique integration of environmental policy system. After 50 years of development, the objectives, principles, content, internal integration and external internationalization of EU environmental policy have undergone significant changes. In the process, the EU's environmental policy has matured stably. EU environmental policy reflects the development trend of world environmental policies, so it also makes the EU's environmental policy valuable to research. The EU's environmental policy is a generic term of EU policies and laws on the development of environmental issues. Broadly speaking, the EU's environmental policies, including environmental policies related to EU environmental law and non-legal nature. The EU is the first coordinated action among Member States on environmental issues, a standardized regional organization. As early as 1970 the EC presented the first environmental slogan "Environment without borders" embodies the idea in protection of national boundaries. After 30 years of development, the EU's environmental policy and environmental protection practices has made great achievements. The EU set up a special environmental institutions, several developed environmental action program adopted over 200 environmental legislation, the EU and its member states have higher environmental awareness, environmental protection and sustainable development strategies have been walking in the world forefront. 6 Therefore, what stages did the EU's environmental policy go through? In these stages, how did the EU itself, Member States and local governments impact the development of environmental policies? what will be the trend of EU environmental policy? How to evaluate the EU's environmental policy? This thesis will attempt to use multi-level governance theory as analytical framework to make a comprehensive and elaborate analysis in the development of EU‘s environmental policy.