With the increasing shortage of water resources, transboundary water disputes will be more and more, international tribunals will be more involved. Analyzing the role of the International Court of Justice in settling the Case Concerning the Gab Nagymaros Project between Slovakia and Hungary, one may find that the tribunals sometimes can not correctly understand and distinguish the relationship between the pursuit of the ideals of justice in the science of law and the law’s seeking elimination of the concrete disputes. Therefore, in addressing a transboundary water dispute, the watercourse State should make careful and wise choices when making a decision of whether choosing an international tribunal as a method of dispute resolution, as well as how to choose the applicable law employed in settling the dispute.