The synergetic method of dry season operation of cascade reservoirs is an important part of the joint operation of cascade reservoirs. A research was carried out in the background of the cascade reservoirs including Xiluodu, Xiangjiaba, Three Gorges and Gezhouba. The runoff in dry season was separated into three groups including high hydrological years, normal hydrological years and low hydrological years. A stochastic optimal dispatching model for cascaded reservoirs in dry season was established taking the maximum mathematical expectation of generated energy in each group as the object. A calculation was carried out considering the different water levels at the beginning of dry season and the synergetic schemes of different hydrological years were obtained. The result showed that the synergetic method of dry season operation in Three Gorges cascade reservoirs coulf increase overall generated energy in some degree. The water supply benefit was great under the condition that the inflow was low and the beginning water level of Three Gorges was low. At last, the synergetic strategy of dry season operation of Xiluodu- Three Gorges cascade reservoirs was summed up to guide the practical operation of the downstream Jinsha River and Three Gorges cascade reservoirs.