The Black Stork (Ciconia nigra) is a national first-class wildlife protection animal in China. From 2010 to 2018, we used line transects and point transects to monitor the population of Black Stork at Zhangye Heihe Wetland National Nature Reserve. We also collected the breeding information of Black Stork in our study area. According to our investigation, the largest population of Black Stork appeared in late September every year, ranging from 120﹣430 ind. During the spring migration season, Black Stork arrived at our study area in March and April, while some individuals bred here and others kept migrating. During the autumn migration season, some Black Storks arrived in the middle of August, while most of them arrived in late September, and they stayed here until late October. A small population stayed in this area during winter. From 2012 to2018, we systematically checked 9 nest sites and found 37 active nests totally. All the nests were built on cliffs, mainly built by twigs. The nests were plate-shaped, with outer diameter of 110﹣170 cm, inner diameter of 40﹣70 cm, inner depth of 4﹣7 cm, height of 45﹣84 cm. Egg laying period lasted 6﹣8 d and the clutch size was 4 or 5. According to measurements of 19 eggs, the short axis was 47﹣55 cm and the long axis was 63﹣71 cm. Parents began incubation after the first egg was laid and both sexes participated in incubation. The incubation period lasted 33 or 34 d and it took 3﹣5 d for all nestlings hatched. Both sexes brooded the young. Nestlings needed up to 70 days to gain flight ability and they usually fledged at 100 days old. According to the 37 nests, the hatching rate was 55.2%, and 2.6 ± 0.6 nestlings fledges per nest on average. We hope our findings could provide more information for conservation and comparative study of Black Stork.