In order to study the flood characteristics of Ganjiang River Basin, based on the daily flow data of the Ganjiang River Basin Control Hydrological Station for 70 years from 1950 to 2019, the annual maximum peak discharge and the maximum daily flood volume were studied, and the joint distribution of flood peak and volume was studied through the copula function, and the joint return period was analyzed. The results showed that the Ganjiang River flood peak and volume maintained good consistency, and both showed a decreasing trend; The optimal distribution of flood peak and flood volume were both gamma distribution functions; The Frank copula function can fit the correlation between the flood peak and flood volume of the Ganjiang River well. When the univariate return period of flood is 5 years, the actual return period is 4.89～5.12 years; when the univariate return period is 100 years, the actual return period is 72.51～161.05 years.