The UK Finally in pursuance of a referendum at June 2016 made a decision to exit from European Union and announced it to the European Union at the end of march 2017. Undoubtedly the separation of The Britain from EU will have significant political, legal, economical, cultural and social effects on the issues inside the territory of each party, the relationship between them and also between them and other states all over the world. Furthermore, this separation will have great influence on the international order which should be considered unavoidable. This article in order to cover the legal aspects of Brexit, is intended to consider the consequences of Brexit on the international law. It is obvious that the separation will cause remarkable differences in human rights, environmental law, the law of investment and the related issues considering the European common market and commercial contracts. Moreover, Brexit is important as a law-making process since it could change the contractual obligations of The European Union itself and at last it seems that brexit has a significant influence on world community and international law as a whole.