Abstract: In order to quantify the equivalent relationship of flood control capacity utilization between different reservoirs when encountering different types of flood, this paper analyzed the influence of river flood routing on reservoir flood control operation based on Muskingum model, and then put forward a concept of utilization equivalent ratio of flood control capacity of reservoir groups.Taking the joint flood control compensation dispatching of Jinping I,Ertan, Xiluodu, Xiangjiaba and Three Gorges Reservoir to Zhicheng Station in Changjiang river as an example, the equivalent ratio for flood control capacity utilization of upstream reservoirs to Three Gorges Reservoir was analyzed under six representative design floods.The results showed that:(1) the equivalent ratio for flood control capacity utilization of the upstream reservoirs to the Three Gorges Reservoir were no less than 1,and it increased gradually with the increasing distance between the upstream reservoir and the Three Gorges Reservoir;(2) with the decrease utilization of flood control capacity of the Three Gorges Reservoir, the equivalent ratio for flood control capacity utilization of the upstream reservoir to the Three Gorges Reservoir increased gradually;(3) The larger the proportion of controllable flood from upstream reservoir to the flood inflow of the Three Gorges Reservoir, the smaller the equivalent ratio was;(4) the corresponding equivalent ratio was negative correlated with the duration of excessive flood in Zhicheng Station, and it reached to 1 gradually.