Abstract: The determination and guarantee of ecological water level in rivers are of great significance for enhancing urban adaptability, improving ecological environment, reducing construction costs, and solving water resource problems. Taking Suyu District of Suqian City as an example, with reference to the water storage cascade of different rivers in the study area, suitable ecological water level control sections were selected, and hydrological, aquatic organism growth, and landscape factors were comprehensively considered. Different methods were used to calculate the minimum ecological water level of the river section, and the water level calculation values of the relevant rivers in the same water storage cascade were compared. The outsourced value was taken as the final basic ecological water level. Combined with the actual operation and water storage situation of the river network in the area, the target ecological water level was determined, and safeguard measures such as river damming and storage, reclaimed water utilization, and drainage scheduling were proposed. The basic ecological water levels of the four water storage cascades in the research area are 18.7 m, 13.9 m, 15.4 m and 14.9 m, respectively, and the target ecological water levels are 19.5 m, 14.5 m, 16.5 m and 16.3 m, respectively. The research results provide reference for determining and ensuring the ecological water level of river channels in the northern plain river network area of Jiangsu Province.