This article explores the reconsideration of the traditional concept of the source of international law by examining the role and development trend of soft law regulating international environmental relations. To achieve this objective, the article first analyses the overall development of soft law to clarify its meaning, characteristics, and practical legal implications. Through this analysis, the article finds limitations in the traditional understanding of international law sources as the form in which legal norms are contained. The article argues that the concept of source of international law should be redefined to reflect the changing practice in the making and implementing of international law. It concludes that the acknowledgment of international soft law norms, particularly in the realm of international environmental law, is a new law-making method in the 21st century, one that requires defining the sources of international law as all elements that contain the basis for the formulation and implementation of international law.
