International law has provided solutions to deal with international crises so that disputes between governments can be resolved amicably and peacefully. Despite the effectiveness of international law in managing disputes and resolving conflicts, in the case of Russia and Ukraine, it seems that the proposed solutions do not have the necessary efficiency and are facing serious challenges. By analyzing and investigating the events in Ukraine and its transformation into a global crisis, it seems that the parties' lack of understanding of each other's positions and security demands and other reasons such as: differences in the interpretation and application of international law, conflict of interests, lack of mechanism enough to implement the decisions and the influence of the great powers, is one of the basic challenges of the international law system in the process of resolving conflicts between Russia and Ukraine. According to the findings of this research, It has been done descriptively and analytically; The most important article of the UN Charter regarding the prohibition of resorting to force in order to curb military conflicts between states is insufficient. The contradiction and incompatibility of paragraph 4 of Article 2 of the Charter with the recognized national interests of governments, especially superpowers, is the main reason for violating this rule. Therefore, the international law system should draw more realistic and up-to-date methods and establish an effective and definitive executive mechanism for resolving disputes.