Climate change and human activities have changed the temporal and spatial distribution of natural runoff, and the change of hydrological conditions has become one of the main reasons for the degradation of aquatic ecosystems. The research on ecological discharge can provide scientific basis for the optimal allocation of water resources, sustainable development and utilization and restoration of aquatic ecosystem in Ganjiang River Basin. Using RVA, Q90 (90% guaranteed minimum daily average flow method next month), NGPRP and other hydrological methods, the daily flow data of Ganjiang River basin for more than 60 years were studied, and the ecological flow process of Ganjiang River basin was analyzed. Tennant method was used for comparative analysis. Finally, the suitable ecological flow under the combination of RVA in flood season and multi-year daily flow drainage frequency method in non-flood season (90%) was selected as the lower reaches of Ganjiang River. Appropriate monthly ecological flow value. Among them, April to June is the main flood season of Ganjiang River, and the ecological flow value required is the largest, 1520 m3/s, 1988 m3/s and 1924 m3/s, respectively. Compared with the measured flow of Waizhou Station, it is found that the ecological flow of rivers in the lower reaches of the Ganjiang River is difficult to be guaranteed. The proportion of non-compliance is higher than 13%, especially in January and November.