Under the environment of power market, the interest game among the investors of cascade hydropower stations in the basin brings great challenges to the traditional cascade hydropower dispatching. Based on this, a multi-agent game market transaction model of cascade hydropower based on blockchain is proposed. Firstly, the transaction mode of cascade hydropower market based on blockchain technology is established, and the traditional block chain encryption algorithm is improved. Secondly, in view of the inconsistency between the geographical distribution of hydropower stations and the economic subordination, a multi-agent day ahead market trading model of cascade hydropower stations is established. Then, the multi-agent cascade analysis method is introduced, and the multi-agent operators and dispatching center of cascade hydropower stations are regarded as different stakeholders, and the operators" profit maximization and social welfare maximization are respectively taken as the objectives to carry out the parallel solution, so as to realize the unified coordination and optimization of the multi-agent cascade hydropower stations in the local and the whole. It is applied to the cascade hydropower system in the main stream of the Yangtze River. The results show that the proposed method not only makes use of the security attributes of the blockchain itself, but also ensures the maximization of the benefits of the cascade hydropower joint operation while considering the cooperation between power stations.