Oriental Pied Hornbill (Anthracoceros albirostris) has been listed as a critically endangered species in China because of its decreasing population and small range. The breeding ecology of Oriental Pied Hornbill in China is poorly known. We observed the breeding behaviors of a couple of Oriental Pied Hornbill in karst forest, during 2019 and 2020. They built their nest on a steep limestone cliff between April and July. The incubation and nestling period were estimated about 35 and 55 days, respectively. Two nestlings were successfully fledged in each year. Male mainly fed fruits of figs to female and their nestlings. There was no obvious feeding peak by male in day. Our results implied that Oriental Pied Hornbills had adapted the karst habitat in breeding behavior.