Abstract: Artificial water replenishment is an important measure to restore the health of urban river and lake ecosystems and improve urban landscape. In order to achieve the goals of water quality maintenance, biodiversity, recreation, and navigation of small cruise ships, this paper studies and developed a water demand estimation method of urban rivers and lakes under the condition of lack of observed data. Based on existing studies at home and abroad, key control factors such as velocity of the river flow, water depth and water change cycle were reasonably determined, and the appropriate value range of key control factors was proposed according to the eco-hydrological characteristics of rivers and lakes in northern China, providing references for water demand estimation in related research and practice of artificial water replenishment.