Abstract: River ecological water demand is the minimum water consumption that must be guaranteed to maintain the stability of ecological environment function in the river, which can provide a scientific and theoretical basis for river ecological environment governance and rational development and utilization of water resources. Due to the phenomena of continuous bottom freezing and cutoff in winter, the contradiction between the development and utilization of water resources and the ecological environmental water demand which intensifies the river of the cold regions in northern China. So an important problem is how to determine the ecological water demand of rivers in cold regions. According to the variation characteristics of river runoff in cold regions, considering the freezing period and non-freezing period, and selecting the monthly average runoff with ninety-five percent assurance rate and the multi-year average monthly runoff as indicators, this paper improves the annual distribution method of river ecological water demand. Taking five main hydrological control sections in the Huma River Basin in the high latitude region as the research object, the runoff data is taken in total of sixty-one years, measured sections from 1956 to 2016 are selected, and the basic ecological water demand of the main control sections of the Huma River is calculated by using the improved intra year distribution method, and the calculation results are compared with those of Montanan（Tennant） and those of other methods. The results show that:（1） the ecological water demand of the sections of the main hydrological stations in the Huma River Basin in the flood season（wet season） accounts for 25.8%～27.8% of the annual average runoff in the same period for many years. The cross-section ecological water demand of each main hydrological station in non flood season（normal season） accounts for 19.1%～24.0% of the annual average runoff in the same period over the years. The analysis and calculation results are consistent with the river state corresponding to the evaluation standard of Montana method（Tennant） and the ecological function goal defined by the concept of basic ecological water demand of the river.（2） The improved intra year distribution can well reflect the natural runoff of rivers in the northern cold region during the flood season, the non-flood season and the real change process and law of low water and even continuous bottom freezing in the freezing period, which can meet the ac tual needs of the river ecological function protection target for runoff in the northeast cold region, and meet the annual dynamic demands of the river ecological hydrological process for runoff. As a result, it can be popularized and applied to the calculation of the basic ecological water demand of rivers in the cold region. The actual demand of the river ecological function protection target for the runoff can be applied to the calculation of the basic ecological water demand of rivers in cold regions.