"Wang Qi" is that experts can forebode the good and/or ill omens from observing the changes of clouds in the sky. The Emperors in the Qin and Han Dynasties had the big trust in "Wang Qi", but the trust declined over time. It was prevalent again in Northern and Southern Dynasties but not in favor after Sui and Tang Dynasties. This article indicates that the waning "Wang Qi" was caused by the establishment of Monarchy and the raising of other numerologies.