The jurisdiction of the ICC is complementary to national jurisdictions and generally，national courts have primary jurisdiction over crimes regulated in the Rome Statute.Therefore，the ICC only carries out its jurisdiction when there is a possibility of impunity.However，how to realize the distribution of jurisdictions between the ICC and national courts relies on the criteria of admissibility.Article 17 of the Rome Statute regulates the criterion of case admissibility.This article will discuss not only the theory of the principle of complementarity but also combine with case study in order to discover the problems of the application of the principle of complementarity in practice.Through this normative analysis，it is not only helpful to distinguish the meaning of the related regulations in the Rome Statute，but also provide state parties and non-state parties stronger legal protection on their national interests.