The religions philosophy is a very significant aspect in Hegel's philosophy whose theology is mainly expressed in his religions philosophy, especially in his discussion on God and Christianity. Hegel, as a Lutheran believer, always holds the very truth of Christianity. Hegel proved that Christianity is the only religion which has authority and truth in virtue of reason in his construction of the religions philosophy. This paper mainly focuses on the analysis of Hegel's thoughts of Christianity, especially on his religions philosophy, attempting to explore how Hegel proved the truth and authority in his philosophy.