Based on the developed flood routing model for the middle reaches of the Huaihe River, simulation and analysis of the relationships between the abandonment of several flood way districts and influences of flood diversion of specific flood plains upon variations in the water level are carried out in this study. The model is applied to analyze the influences on the water level in the main stream of the Huaihe River with respect to the abandonment of flood way districts of the Shangliufangdi and Xialiufangdi. From the analysis results of the usages of all flood way districts it is found that the peak stage only increases by 2 cm and 4 cm after discarding the Shangliufangdi and Xialiufangdi flood way districts when the Huaihe River suffers from floods with a frequency of 50 years and 100 years respectively. This verifies the rationality of abandoning both the above-mentioned flood way districts. This model is also used to analyze the variation in the water level of the main stream of the Huaihe River with respect to the use of the Huang-su flood plain when the Huaihe River suffers from floods with a frequency of 200 years. The analysis and simulation results show that the corresponding water level of the levee breach in the main stream of the Huaihe River decreases by 10-14 cm after discarding the Huang-su flood plain within 3-4 days. Additionally, the water levels of the upstream and downstream levee breach in the main stream of the Huaihe River also decrease at different degrees. Obviously, the use of the Huang-su flood plain can significantly reduce the water level of the main stream of the Huaihe River, so as to efficiently protect the important embankments nearby and save more time and space for flood control.