Based on abundant and detailed basic data, a hydrological and hydrodynamic model was established. The influence of the urban drainage of Suzhou, Wuxi and Changzhou on the water level of the Jiangnan Canal under the current scheduling scheme, optimal scheduling scheme and no scheduling scheme was analyzed. The characteristics of urban flood and regional drainage were also analyzed. The results show that the current scheduling scheme can reduce the urban flood peak water level of Changzhou, Wuxi and Suzhou by 0. 28-1. 10m compared with the no scheduling scheme, revealing that the large surrounding of the urban area can effectively reduce the flood water level and ensure the safety of the urban area. However, the water level of the Jiangnan Canal increases with the rainfall and the drainage in Suzhou, Wuxi, and Changzhou. If the optimal scheduling scheme of which the beginning pumping stage rises by 0. 17-0. 30m appropriately is adopted, the water level of the canal will decrease by 0. 00-0. 12m. It shows that on the premise of not greatly increasing the urban flood risk, the amount of urban drainage can be appropriately reduced to decrease the water level of the Jiangnan Canal and the relationship between urban and regional flood control can be coordinated.