Abstract: Based on the Three-Source Precipitation Product developed by China Meteorological Administration, the inversion ability of IMERG V06 Final precipitation product of Global Precipitation Mission (GPM) on extreme precipitation in the lower reaches of the Jinsha River was analyzed from the aspects of the accuracy evaluation of extreme precipitation indices and the detection ability of extreme precipitation by using seven evaluation indicators such as correlation coefficient, relative deviation, normalized root mean square error, hit rate, false alarm rate and critical success rate. Results show that the IMERG precipitation product can retrieve the spatial distribution characteristics of extreme precipitation, and the effect is good in strong and weak rainfall areas. In most regions of the basin, IMERG precipitation product overestimates the extreme precipitation indices, which is more obvious in high altitude mountainous areas. The inversion effect of IMERG on Rx5day precipitation is better than that of other extreme precipitation indices (extreme daily precipitation, maximum single-day precipitation, strong precipitation and heavy rain days), with higher correlation coefficient, lower relative deviation and lower normalized root mean square error. IMERG precipitation product has great seasonal and regional differences in the detection potential of extreme precipitation events. The capture ability in summer is better than that in other seasons, and the capture ability in low-altitude areas is better than that in high-altitude areas. In summer or low altitude areas, IMERG precipitation product has high hit rate, high critical success rateand low false alarm rate.