Emperor Cheng of Han, personal name Liu Ao, was an emperor of the Chinese Han dynasty ruling from 33 until 7 BC. He succeeded his father, Emperor Yuan. Under Emperor Cheng, the Han dynasty continued its growing disintegration as the emperor's maternal relatives from the Wang clan increased their grip on the levers of power and on governmental affairs as encouraged by the previous emperor. Corruption and greedy officials continued to plague the government and, as a result, rebellions broke out throughout the country. Emperor Cheng died childless after a reign of 26 years; both of his sons by concubines had died in infancy. One of them starved to death and another was suffocated in prison. The babies and their mothers were killed by the order of Emperor Cheng's favorite consort Zhao Hede, with the implied consent of the emperor. He was succeeded by his nephew, Emperor Ai, whose death was followed by Wang Mang's rise to power.

Throughout Chinese history, "Emperor" was the superlative title held by the monarchs who ruled various imperial dynasties. In traditional Chinese political theory, the emperor was the "Son of Heaven", an autocrat with the divine mandate right to rule all under Heaven. Emperors were worshiped posthumously under an imperial cult. The lineage of emperors descended from a paternal family line constituted a dynasty, and succession in most cases theoretically followed agnatic primogeniture.