Relevant to the relationship between natural sciences and humanities as well as that between epistemology and ontology, the issue of truth is one of the core subjects in modern Chinese philosophy. Regarding the essence of truth, FENG Qi accepts the correspondence theory based on practice, believing that truth means the unity of subjectivity and objectivity and the correspondence of cognition and reality or things. Such concrete truth manifested in the correspondence can be grasped by dialectical logic thinking on the one hand, and correctly stated in the form of propositions on the other. Meanwhile, FENG Qi elaborates on the concreteness and freedom of truth, claiming that truth is objective, comprehensive, historical and relative, and the objectivity of truth lies in the coherence of human nature and the Dao of nature (tian dao). In this sense, truth is in accordance with both natural laws and the purpose of humans, demonstrating the unity of the principle of nature and the principle of humanity. Hence, FENG Qi argues that in wisdom we will realize the unity between natural sciences and humanities and that between epistemology and ontology.