Papilio bianor, the Common peacock or Chinese peacock black swallowtail emerald or Chinese peacock is a species of butterfly in the family Papilionidae, the swallowtails. It is native to Asia. It is the state butterfly of the Indian state of Uttarakhand.
This species is variable in size. Individuals emerged in the spring reach 4 to 8 centimeters wide, while those emerged in the summer can reach 12 centimeters.