To explore the temporal and spatial characteristics of ecological base flow value, Taking Zhoukou and Shenqiu reach in the middle reaches of Shaying River as the research object, the influence factor matrix of ecological base flow was constructed according to the data of rainfall, runoff, evaporation, per capita water consumption, water quality attainment rate and per capita GDP from 2008 to 2021. Based on the coefficient of variation method and the ecological base flow value of the reaches in 2021, the inter-annual change rule of ecological base flow value of each reach was analyzed. The results were as follows: (1) The ecological base flow value of Zhoukou section fluctuated between 0.8939 and 4.2571 billion yuan, with that of Shenqiu section between 0.6765 and 2.2044 billion yuan; In both reaches, water quality was the most important factor, followed by discharge and precipitation factors; Economy, evaporation and water consumption had little effect on ecological base flow value of river. (2) Ecological base flow value of each reach was affected by amount of resources in certain extent. The average annual discharge and precipitation of Shenqiu Reach were greater than that of Zhoukou Reach, but its value of ecological base flow was smaller than that of Zhoukou Reach on the whole, indicating that ecological base flow had scarcity characteristics of water resources. Conclusion: The coefficient of variation method is suitable for the temporal and spatial change analysis of ecological base flow value of river, and which can obtain more objective results, identify the primary and secondary factors affecting ecological base flow and its value, which is conducive to promote the further development of non-point source pollution control and ecological base flow protection, to ensure the ecological security of the basin.