[Objective] Taking the Yangling Agricultural Hi-tech Industries Demonstration Zone with the surrounding water system in Shaanxi Province as the research object, this paper analyzed the relationship between the urban construction of the developing city and the ecological base flow of rivers around the city in order to provide a scientific basis for the ecological water planning of the basin and the rational allocation of river water resources.[Methods] The minimum monthly average flow method was used to calculate the ecological base flow of the rivers. The relationship between the minimum monthly average flow and urban construction area was analyzed to estimate the water warning line. And the impact of urban construction on the protection of ecological base flow was analyzed from the perspective of sediment transportation and self-purification of water.[Results] ① The ecological base flow of Weihe River, Qishui River and Xiaowei River around the Yangling Demonstration Zone was about 6.0, 0.2 and 0.1 m³/s, respectively, which could be used as the basis for the water use planning and water resources allocation for the three rivers in this area. ② The internal relationship between the minimum monthly average flow of Xiaowei River and the construction area of Yangling Demonstration Zone was exponential. The warning value of urban construction area was 60 km² to ensure the ecological base flow of Xiaowei River. ③ The monthly average concentration of total nitrogen and total phosphorus of Xiaowei River exceeded the V-class water quality standard. The current situation of high pollution in winter and spring made it more severe and urgent to guarantee the ecological base flow of Xiaowei River.[Conclusion] The urban construction of Yangling Demonstration Zone is closely related to the ecological base flow of rivers around the city, especially Xiaowei River. Sponge city construction is an important development direction for the developing cities in the future.