Abstract: The Huai River basin has been severely affected by rainstorm and flood disasters.It is of great significance to scientifically estimate the changes in extreme precipitation under global warming of 1.5 ℃ and 2.0 ℃ in the Huai River basin for flood control and adaptation to climate change.Based on the projections of the 22 GCMs(Global Climate Models) issued in the CMIP6(the sixth phase of the Coupled Model Intercomparison Project), the spatiotemporal variations of extreme precipitation and changes in future risk over the Huai River basin are investigated by using the modified reliability ensemble method, probability ratio method and six extreme precipitation indices.The results show that: ① The modified reliability ensemble method performs better in simulating extreme precipitation indices over the Huai River basin than the single GCM and arithmetic mean ensemble approach.② The timing spans of 1.5 ℃ and 2.0 ℃ global warming approximately occur in 2017—2046 and 2026—2055, respectively.③ The increase of extreme precipitation indices under 2.0 ℃ global warming is 1.4 to 2.6 times of that under 1.5 ℃ global warming, with the largest increase occurring in the northern region of the Huai River basin.④ Under two global warming of 1.5 ℃ and 2.0 ℃, the risk of extreme precipitation has an increasing trend, and the additional 0.5 ℃ global warming from 1.5 ℃ to 2.0 ℃ will result in higher risk over the Huai River basin.For instance, the return period of a 100-year extreme precipitation will likely become to 32-year and 22-year under 1.5 ℃ and 2.0 ℃ global warming, respectively.In the future, extreme precipitation events will probably become more frequent over the Huai River basin.