John Hick's religious pluralism is popular in the field of Philosophy of Religion today. Yet the supporting theory for interreligious dialogue is Karl Rahner's religious inclusivism in the Catholic Church all over the world. The study attempts to exam whether it is the best choice for Catholic world, and whether we may find the difficulties and its suggestions to improve them according the results of the contemporary scholars. Therefore, this article is to classify all the theories of the interreligious dialogue first; then, explores respectively the basic thoughts of pluralism and inclusivism; finally, tries to find out the difficulties and its resolving approaches for both theories.