Abstract: Joint flood forecast and control operation modes of reservoir groups are a key measure to river basin flood control and city flood control and also to the reasonable and optimized allocation of water resources. Joint operation of reservoirs needs to consider not only the constraints and forecast of each reservoir, but also reservoir compensation relationship. Previous trial calculation methods depend too much on empirical factors to obtain true global optimal solutions to such operation problems. This work integrates the optimization technique with a planning flood forecast-based operation, formulates a general form and solution procedure of the forecast operation rules considering forecast errors, and develops an optimal operation model for a reservoir group. This model can solve for the optimized flood control operation rules of each reservoir and its dynamic flood control stages. A case study of the Qinghe and Chaihe reservoirs shows that the joint operation schemes can raise the flood control stages of the two reservoirs by 0.4 m and 0.3 m, respectively, hence increasing the total flood water storage by 62 million m3. The results lay a basis for further studies on flood forecast and control operation of reservoir groups.