Abstract: Based on the precipitation observation data of 98 national and regional meteorological stations in the Three-River Source Region, compared the precipitation products of IMERG and GSMaP satellites, and the applicability assessment was carried out according to the Yangtze River Basin, the Yellow River Basin and the Lancang River Basin. The results show that the median correlation coefficient between IMERG satellite precipitation products and daily surface precipitation observation data is 0.62, the median root mean square error is 4.24mm, and the hit rate can reach more than 0.80, which is obviously better than GSMaP data. The two satellite precipitation products slightly overestimate the precipitation of light rain, but underestimate the precipitation of moderate rain and heavy rain, especially the underestimation of heavy rain. The IMERG underestimate the short-term heavy rainfall, which is the main reason for the underestimation of heavy rain. The average correlation coefficient of the two precipitation satellite products decreases with the increase of the altitude, and the correlation coefficient is the largest in the low altitude area, and the root mean square error is the smallest.