Abstract: Black-necked Cranes (Grus nigricollis) are omnivorous birds, but mainly feed on plants. We studied the herbivorous diets of Black-necked Cranes using microhistological analysis at Dashanbao National Nature Reserve. Our results showed that Black-necked Cranes fed on a total of 43 plant species. The Trifolium repens, Carex muliensis, Picris hieracioides, Origanum vulgare, and Bupleurum gracillimum were the main food plants, accounting for 13.04%, 8.51%, 5.99%, 5.15% and 5.28% of the total dry biomass, respectively. Black-necked Cranes had selection on organs of plants(F=10.095, df=3, P=0.000)and preferred leafs (63.91%) than other organs. In the future wetland restoration act, we suggested Trifolium repens as the main plant species for the recovery of the plant community and increase food source of Black-necked Cranes.