Abstract: Based on 8 commonly used extreme climate indices, the research evaluates and analyzes the simulation capabilities of the coupled model intercomparison program in phase 6 (CMIP6) for extreme temperature and precipitation characteristics in Southwest China from 1990 to 2014. It also estimates the trend of extreme climate events from 2023 to 2100, using a combination of four shared socioeconomic pathways and representative concentration pathways (SSP−RCP). The results show that: ① most models of CMIP6 can reasonably simulate the gradual increase of extreme temperatures from west to east in southwest China, and larger spatial distribution of extreme precipitation in its southern margin. The simulation effect of extreme temperature is better than that of extreme precipitation; ② The estimated extreme high temperatures in the southwestern region from 2015 to 2022 are lower than the observed values, with higher extreme low temperatures and lower extreme precipitation indices; ③ In the next four scenarios from 2023 to 2100, extreme high temperatures, warm day numbers, and extreme low temperatures all show an upward trend, while cold day numbers show a downward trend, indicating that the probability of high-temperature-and-heat-wave weather in Southwest China would increase significantly in the future, and the probability of low-temperature-and-cold damage would decrease. The precipitation intensity, the annual maximum 5−day precipitation amount(Rx5day) and the annual total heavy precipitation show an upward trend, indicating that the intensity and total of precipitation in southwest China would increase in the future.