Abstract: With the acceleration and permeation of economic globalization, human society is Keeping progress, meanwhile, people's material and cultural needs are also gradually improved, the environmental problems associated with it have become increasingly prominent. The deterioration of the environment brings Environmental issues to the world. The European Union (hereinafter, the EU) is a regional international organization with the highest degree of economic and political integration in the world. It plays a decisive role in international environmental affairs. In solving environmental problems, the EU has accumulated many successful experiences, which provides a useful reference for all countries to protect the environment and carry out environmental cooperation. It is worth mentioning that its environmental legal system is of great significance to other countries, and in this area, its environmental principles are the most fruitful and systematic ones among all the areas. Human beings have such a preference to pursuit for better things, so I try to research the principles of the EU environment in this article. There are five environmental principles in the EU basic legal document" Article 174 (2) of the EU Treaty", namely, the polluter pays principle, the prevention principle, principle of rectification at source, the precautionary principle and the integration principle. In order to embark on a comprehensive exposition, in the first part of the thesis ,the author gives an account of the selection background and a brief problem description, and research purposes , meanwhile gives brief introductions to research methods, research limition,research frameworks; In the second part of the thesis the author tries to explain some related issues such as the outline of the development of UN environmental law and environmental principles, at the same time, gives some introductions to concept of sustainable development. In the third part of the thesis, The author spent a great deal of energy on each specific principles. For each principle, I start from its concept, then analyze its origin, thirdly expound the basic content, specific application and the current issues and concerns.In the fourth part of the thesis, on the basis of the third part , the author Conducted a further analysis——the common factors and different factors which were abstracted out from the third part ,with a view to clearly show the essence of environmental principle; in the last part of the thesis, the author draws a simple conclusion throughout the text and prospects the follow-up research issues.