Abstract：Heaven worship is an important content of nature worship of the Khitan people. The Khitan emperors sacrifice to heaven mostly when he wants to pray for the victory before the war; when they celebrate the victory postwar, when they wipe out the hostile party, when they confer empresses and secretary, when foreign countries pay tribute (surrender), when abnormal signs appear; when they go out hunting or when celebrating festivals etc. The ritual sacrificial offerings are cyan cow, white horse, black sheep and white sheep, liquor and dried meat slice, abnormal things and prey, and the sacrifice location is not a fixed place. In the early Liao Dynasty, Khitan emperors worship heaven frequently, but in the Liao Xingzong period, the frequency of heaven worship greatly decreases, when it is affected by the development of Buddhism and the relationships between Liao and Song, Liao and Koryo, which become eased off. This paper discusses four aspects about Khitan emperors’ heaven worship. Thank for experts’ comment.