Abstract: Mandarin duck (Aix galericulata) is a medium-sized duck in Anseriformes order and Anatidae family, which belongs to the national second-class protected wild animal. And its main breeding place is in the northeast regions of China. From December 2018 to June 2019, we observed the reproduction of a mandarin duck population residing in Jiange County, Guangyuan City, Sichuan Province. There were 23 (12♂, 11♀) mandarin ducks in this population. We measured two cave nests and four eggs in the No.01 net. The eggs were oval in shape, white in color, with an average weight of 37.92g and an average length and short diameter of 52×38 mm. Because of the invasion of owls, the eggs of mandarin ducks in the No.01 net failed to hatch and reproduce. The breeding of mandarin ducks in the wild has not been reported in Sichuan Province, which adds a new record of residence and breeding grounds for the population of mandarin ducks in the southern provinces.