[Objective] The drought and waterlogging characteristics in the water source & receiving areas of the middle route of the south-to-north water transfer project were studied, and the risk of "both drought " caused by climate change was analyzed and predicted in order to provide a basis for scientific decision-making.[Methods] Based on daily precipitation data of 265 meteorological stations during 1961-2015 and drought & waterlogging data of past 500 years in the middle route of the south-to-north water transfer project region, the drought and waterlogging characteristics in one water source area(the upper reaches of Hanjiang River) and three water receiving areas(Tangbai, Huaihe, and Haihe river basins) were analyzed, and the efficiency of water transfer in three water receiving areas were calculated. This study also investigated the future drought and waterlogging characteristics under the RCP 4.5 scenario based on the simulation results of 21 CMIP 5 global climate models.[Results] ① In the past 500 years, the probability of occurrence of drought decreased first and then increased in the water source area, In the 20th century, the probability of occurrence of drought in the water source area reached highest in the history(31.7%). ② The Huaihe River basin showed the highest efficiency of water transfer(87.3%) while the Tangbai River basin showed the lowest(78.4%). ③ Since the beginning of the 20th century, the unfavorable probability at each river basin and the water source region reached a maximum. The probability of simultaneously occurrence of multi-year droughts in the water source area and Tangbai & Hai river basins is greater than Huai River basins. ④ The water transfer efficiency during the autumn flood season(SON) is the highest, and that in all the 3 basins during the non-flood season is over 80%. ⑤ The efficiency of water transfer in each water receiving area in the future is above 87%.[Conclusion] The synchronous encounter probability of drought in water source & receiving areas in 20th century reaches a maximum in the past 500 years. The simulations show that it will benefit the water transfer of the project in the future. However, in late 21th century, the risk of waterlogging in both the water source and water receiving areas simultaneously will increase.