Abstract: Based on the precipitation data observed by 54 meteorological stations in the eastern part of northwest China during the period of 1960-2009, the variation of precipitation in this region was analyzed using the Mann-Kendall test and wavelet analysis. The main results were as follows: (1) Precipitation in the study area was in a slight decrease trend, the precipitation reduction was more obvious after 1990, and the variation of precipitation in area Ⅱwas more significant than that in area I; (2) The precipitation frequency in the study area was dominated by weak and moderate precipitation events, which accounted about 70% of the total precipitation days, and the decrease of weak precipitation frequency was obvious; (3) The proportion of moderate and heavy precipitation accounted for more than 75% of annual precipitation. Decrease of annual precipitation was mainly caused by the decrease of moderate precipitation; (4) The results of wavelet analysis revealed that there were the 3year and 5year fluctuation periodicities of annual, moderate and heavy precipitation, the periodicities of moderate and heavy precipitation in area I were completely different from those in area Ⅱafter the 1970s, and the decrease of moderate precipitation was closely related to the variation of moderate precipitation in the 1970s.

Key words: precipitation frequency, precipitation intensity, Mann-Kendall test, wavelet analysis, eastern part of northwest China