The "Watershed-Scale Constructed Wetland Water Purification Method" primarily purifies water by simulating the ecological processes of natural wetlands and leveraging the synergistic effects of substrates, aquatic plants, and microorganisms. This method is suitable for water quality improvement in watershed systems such as rivers and lakes, and is particularly effective in non-point source pollution control. The construction of wetlands is of great significance for improving the ecological environment along river corridors and enhancing the quality of the urban environment.