The mean and extreme temperature and precipitation changes in the future were explored by using the global high-resolution downscaled projections from the Coupled Model Intercomparison Project phase 5 (CMIP5). The ranges and sources of projection uncertainties of the mean state changes are also estimated. Results show that: (1)under both RCP4.5 and RCP8.5 scenarios,the mean temperature and precipitation, and extreme temperature and precipitation increase, while the consecutive dry days decrease, over TP in the 21st century. The rates of climate changes over TP are faster than global mean, and the changes over TP are 1.5—3 times higher than the global average at the end of 21st century.(2)The response of TP to a half-degree warming increment is significant in both mean and extreme temperature, mean and extreme precipitation. (3)Scenario uncertainty shows relative smaller contributions for the near-term projection than for the long-term. Under the same emission scenario, internal variability dominates the near-term uncertainties of TP mean temperature projection, but in the long-term,its contribution falls below 10%.Both model uncertainty and internal variability contribute to the mean precipitationchanges, andthe contributions decrease with time. The largest uncertainty in TP precipitation projection is located at the western and northern edges of TP, where the noise-signal ratioislarger than 6.