In order to solve the problem that the reservoir groups in the middle reaches of the Ganjiang river have low power generation capacity due to the lack of a unified and effective joint dispatch mode，this paper explores the joint power generation and compensation benefits of the cascade reservoir groups in the middle reaches of the Ganjiang river，and studies the compensation benefits of reservoir power generation dispatch in different typical years by studying the maximum power generation as the objective function under the optimization dispatch and joint optimization scheduling of a single reservoir and the joint optimization dispatch of the Ganjiang river reservoir group.The results show that under the typical years of abundant water (1995)，dry year (1991) and normal water year (1985)，the joint operation of reservoirs increases the power generation by 0.01%，0.55% and 0.91% compared with the single reservoir dispatch，and the corresponding reduction of surplus water is 2.26%，5.1% and 10.72%，and the compensation benefit is more obvious in the year with less water.The results can provide a theoretical basis for the analysis of the compensation benefit of joint operation of cascade reservoir groups in the middle reaches of the Ganjiang river and the cooperative scheduling of cascade reservoir groups.