Zhangjiakou city is the water conservation area and ecological function supporting area of Beijing, the capital of China. The upper reaches of Yongding River in Zhangjiakou play an important role in preserving water resources. In order to get a better understanding of the ecological value of water resources in the study area, various water ecological service functions were quantitatively evaluated in this study. With 2017 as the base year, and the InVEST model and market value method, the water supply in the study area was comprehensively evaluated and intuitively expressed by means of space and currency. In the study area, where spatial data were difficult to obtain, soil and water conservation and biodiversity values were evaluated with the equivalent factor method. The aquatic ecotourism value was calculated with the apportionment method. The results show that the total value is ￥ 5.514 billion, accounting for about 67.35% of the GDP (￥ 8.187 billion) of Zhangjiakou city. The water supply value, hydropower generation value, aquatic product production value, leisure and entertainment value and other direct service values reach ￥ 2.864 billion. Soil conservation, river sediment transport, biodiversity, and other indirect service values reach ￥ 2.650 billion. Water supply, recreation, and soil and water conservation functions play an important role in enhancing the value of regional aquatic ecosystems. The ecological value and economic value per unit area of the study area are ￥ 35 million and ￥ 23 million, respectively, and the ecological value is much higher than the economic value. At the same time, the comprehensive use of the above assessment methods has improved the reliability of the evaluation method and has certain reference significance in the areas without enough basic data.