Because of its unique location and environmental characteristics, Huangshui river basin has become the most important ecological safety defence in the east of Qinghai province, in this paper, carbon fixation and oxygen release, water conservation, soil conservation and biodiversity were selected to evaluate the ecosystem function of Huangshui river basin.The evaluation results show the ecological function of the riversides of the main stream of the Huangshui river is obviously lower than that of other regions, it has become a very salient ecological fragile zones in the ecological defence, especially the area is banded from east to west, to some extent, it blocks the energy flow, material flow and information flow of the ecosystem from north to south, and affects the overall ecological service function of the ecological defence.