The study of ecological water demand thresholds is important for improving the diversity, stability, and sustainability of river ecosystems and the management of river ecological water demand. In response to water and ecological environmental problems such as river cutoff, severe water pollution, and high sediment content in the Gansu section of the Yellow River Basin, the ecological base flow is calculated using annual distribution method based on the monthly runoff data from 30 hydrological stations from 1956 to 2016, and then integrated with the water demand of self-purification and the sediment transport to form the basic ecological flow according to the principle of “taking the big one”. Meanwhile, the target ecological flow is determined by the month-by-month frequency calculation method. Finally, the distribution characteristics of the basic ecological flow and target ecological flow are integrated to obtain the annual ecological water demand thresholds for the rivers, which are then graded and evaluated to ascertain the degree of satisfaction. The results show that the ecological water demand thresholds of the mainstream of the Yellow River during the dry and wet periods of the year are 74.78-393.29 m3/s and 595.35-1, 108.84 m3/s; the tributaries in the section from Maqu to Shangquan are 8.97-26.81 m3/s and 30.16-156.20 m3/s; the tributaries in the section from Shangquan to Anningdu are 0.64-11.93 m3/s and 3.50-124.61 m3/s; the tributaries in the section below Anningdu are 5.67-7.76 m3/s and 14.77-30.53 m3/s, respectively. The ecological water demand thresholds of the rivers are graded as “fair-best” and “very good-best” during the dry and wet periods of the year, respectively; their satisfaction levels of the year were less than 67% for the Zuli and Malian Rivers, and less than 50% for the Datong and Zhuanglang Rivers during the wet periods of the year. The results of the study is conducive to the management of ecological water demand of the rivers and can provide a technical support for the water conservation and optimal allocation of water resources in the upper reaches of the Yellow River.