Due to the impact of global climate changing, the frequency of extreme weather events has increased significantly. The suddenness, harmfulness and unpredictability of the excessive floods are more prominent,posing a great challenge to the collaborative emergency dispatch and the safety of cascade reservoirs. And the dam break or even continuous collapse is the biggest threat to the cascade reservoir. In response to the excessive flooding,it is one of the effective means to realize the comprehensive utilization efficiency of reservoirs to carry out emergency dispatch of cascade reservoirs. In this paper,the maximum water level minimization criteria is selected as the objective function of the collaborative emergency dispatching model for excessive flood, and the Progress Optimality Algorithm method is used to solve the model. Taking the Pubugou Reservoir,the Shenxigou Reservoir and the Zhentouba-I Reservoir in the Dadu River Basin as an example,an emergency dispatching plan for the excessive flood of the cascaded reservoirs in this basin is proposed,the process of its exceeding flood control is calculated. The rationality and reliability of the above model are verified. The results indicate that through the collaborative emergency dispatching of cascade reservoirs,each reservoir will pre-discharge the water in the pre-flood stage,freeing up more reservoir storage capacity,facilitate to meet the possible flood in the later stage,reduce the water level of each reservoir as much as possible,and effectively ensure the flood control safety of cascade reservoirs. The research results have important theoretical significance and engineering practical value for the establishment of emergency dispatch mechanism for the excessive flood of cascade reservoirs in major river basins.