Abstract: Ecological engineering is an important approach for river quality restoration; whilst mathematical models can effectively simulate the water treatment and eco-restoration efficiency. According to the actual data, a hydrological model was constructed and verified via application of the WASP water quality model, which was then used for simulation and evaluation of the river’s main chemical parameters. It was also employed to study the ecological effect on river water quality improvement by constructed wetlands and aerated re-oxygenation. The results showed that the WASP water quality simulation was in good agreement with the water quality measurement, and different ecological restoration scenarios could be predicted and analyzed. Reasonable emission reduction, constructed wetlands and aerated re-oxygenation could reduce the pollutant concentration in the river water, and effectively improve the water quality. Incorporation of the aerated re-oxygenation device into the constructed wetland system would further enhance the river water ecological restoration efficiency. Taking the constructed wetland project with aeration of Yitong River in Jilin Province as an example, the ecological restoration efficiency was analyzed. The results showed that the removal effect of pollutants was the best in summer, and the possible reason was that the air temperature was higher in summer leading to stronger microbial activity in water. This study was of significance to the design and operation of ecological restoration engineering for the polluted river environment.