International environmental law is a branch of international law thatemerged only in the 1970s. As a basic principle of international environmentallaw, the principle of sustainable development has been promoted by theInternational Court of Justice (ICJ) in the trial of international environmentalcases, from the first use of the concept of sustainable development in the GayBaskov - Rakimaro Dam case to the explicit formulation of the principle ofsustainable development in the Pulp Mills on the River Uruguay case, which hascontributed to the judicial The judicial application of the principle of sustainabledevelopment has been facilitated. However, the ambiguity of the principle itselfand the limitations imposed by the principle of State sovereignty have led theICJ to adopt a very cautious and conservative approach to the application ofthe principle of sustainable development. This shortcoming can be improvedby clarifying the connotation of the principle itself and establishing a completeinstitutional system.