Abstract:In order to explore the effect of ecological restoration measures on water quality purification of urban lakes, long-term water quality monitoring was carried out in the treated lake area (the third lake) and the untreated lake area (the second lake) of Liuhua Lake in Guangzhou from June 2019 to June 2021. The results showed that the water quality of the third lake has been significantly improved through the ecological restoration measures such as the improvement of the sediment, the construction of submerged plant communities and the optimization of fish communities. The total phosphorus content, total nitrogen content, ammonia nitrogen content, chemical oxygen demand, biochemical oxygen demand and permanganate index all decreased significantly, and the water quality of the third lake in Liuhua Lake has reached the class IV water standard and above. The indicators of the water body in the second lake did not show a significant downward trend, and were significantly higher than those in the third lake with the extension of time, and remained at the class V water standard.