This article aims at a better understanding of the conception of heaven and man in Han and Sung dynasties by analyzing the related materials in two books , Po-hu tung and I-ch'uan i-chuan. 　　In po-hu tung, heaven and earth are thought of as cosmological, dualistic, and externally deterning principles. They contain normative and natual elements respectively and stand as ruler to man. Society is established on san-kang liu-chi (三綱六紀, The three primary and six secondary relationships) which is a set of familial and political network objectively arranged by heaven. Man is required to performed an ethic according to the corresponding position he holds. The appearance of sages and the ascendency of monarchs are decided by the will of heaven which is dogmatic. 　　In contrast to Po-hu tung, I-ch'uan i-chuan. Contains ontological, monistic, and immanent principle. The creative principle of the universe is good in itself, so is the human nature. The evil results from lack of original good. Propriety and justice are for the purpose of controlling emotions. The principle of human combination is Kan-tung (感通, general commiseration). Monarchs should comply to heavenly principle and people's will, and trust upright and capable subjects. In general. I-ch'uan i-chuan has a rationalistic view on heaven and man.