This is about the Chinese cult of Shangdi. See sky deity for a comparative discussion.
Heaven worship is a Chinesereligious belief that predates Taoism and Confucianism, but was later incorporated into both. Shangdi is the supreme unknowable god of Chinese folk religion. Over time, Shangdi became synonymous with Tian (天 lit. "sky"), or Heaven. The worship of Heaven is highly ritualistic and requires that the emperor hold official sacrifices and worship at an altar of Heaven, the most famous of which is the Temple of Heaven in Beijing.