Based on historical experiments of Coupled Model Intercomparison Project Phase Six (CMIP6), 22 models are systematically evaluated by Comprehensive Rating Metrics (MR). Then 10 models (GFDL-CM4, EC-Earth3, MIROC6, etc.) with reliable performance are chosen to project summer rainfall in the Yangtze River Basin in the future 30 years (2021-2050) under SSP245 and SSP585. The results suggest the total rainfall amount (PRCPTOT), and rainfall intensity (SDII) are projected to be relatively an increased trend by comparison with that in 1981-2010, and the large increase is located in the upper plateau and the middle-lower plains. In contrast, the occurrence of rainfall (R1mm) shows a little change because of opposite signal in upper and middle-lower reaches. The heavy rainfall (R95p) is projected to increase by 9.6% and 16.5% (SSP245 and SSP585), and extreme rainfall (R99p) is projected to increase by 10.2％ and 15.5%. The maximum 5-day rainfall (RX5day) also exhibits an enhanced signal. Besides, the maximum consecutive dry days (CDD) will increase especially in upper reaches. As for different SSPs, the changes in SSP585 are greater than those in SSP245. These indicate there will be not only more rainfall amount and more occurrences of heavy-extreme rainfall events, but also a larger potential increase of droughts. Particularly, an increasing risk of the extreme rainfalls and floods in the middle and lower reaches and drought in the upper reaches deserve more attentions.