In order to analyze the effect for flood control joint operation of cascade reservoirs at the downstream of Jinshajiang in conjunction with Three Gorges Reservoir, this paper investigates two compensation dispatching modes of flood control to the middle and lower Changjiang River. The paper choices two typical years and conducts flood regulation routing in different frequencies in calculation. The results show that the mode of joint operation of cascade reservoirs not only can ensure the reaches of Changjiang River in the upper Changjiang River and Jingjiang River safety, but also can further improve the flood control capacity of Three Gorges reservoir. In comparison with the compensation dispathching mode of the reach of Jingjiang River, it can further decrease the flood diversion of the Chenlingji area if the compensation dispatching mode of flood control of the reach of Jingjiang River takes the flood control of Chenlingji area into account.