Abstract: The daily precipitation observational data of 5 stations of Sichuan from 1960 to 2004 are divided in sections,statistically and power-low distribution analyzed. The result shows that,(1) the daily precipitation of the five sites has a common feature-power-law distribution,and different levels of rainfall for different power-law exponent,to a certain extent,it reflects that the different rainfall patterns with different climate background and the physical mechanism;(2) the light rain exponent is changed very little over time,but the moderate power exponent is changed dramatically. Starting from the late=80,the moderate power in the south and west of Sichuan correspond to the reducing trend with the increase of the power-law exponent,and in the east and north and the plateau of Sichuan shows the trend of increase with the reducing of the power-law exponent. So the changes of total precipitation may be caused by the moderate power changes.