二祭天的礼制《左传》有“国之大事,唯祀与戎”之说。祭祀是头等大事之一,祭天则是祭祀中最隆重的。我国古代自然神崇拜时期,祭日月星辰、风云雷雨、山川河岳以至动植物等活动很普遍,这和世界各民族大同小异。如《九歌》中的东皇太一、云中君、湘君、湘夫人、大司命、少司命、东君、河伯、山鬼都是人格化了的自然神。其中东皇太一成为后来汉代太一即天帝的根据。向汉武帝建议祭太一的谬忌说:“天神贵者太一,太一佐曰五帝。古者天子以春秋祭太一东南郊 The second ritual ceremony of Zuo Zhuan, which is an ritual for the worship of the heavens, has the saying “Great Events in the Country, but You Are the Only One”. Sacrifice is one of the most important things. Sacrifice is the most solemn sacrifice. During the worship of natural gods in ancient China, activities such as festivals, moons and thunderstorms, mountains and rivers and even animals and plants were common. This is very similar to the peoples of the world. For example, Dong Huang Tai Yi, Yun Zhongjun, Xiang Jun, Xiang Xiang, Da Si Ming, Shao Si Ming, Dong Jun, He Bo, and Shan Gui in Jiu Ge are all humanized natural gods. Among them, Taiji Donghuang became the basis for Taidi, the Emperor of Heaven in the later Han Dynasty. To Han Wudi’s suggestion of offering to worship Taiyi’s jealousy: “The god of heaven is Taiyi, Taiyi and Sawu are the five emperors. The ancient gods took the spring and autumn festival to the southeastern suburb of Taiyi.