Abstract: Trends in frequencies of daily precipitation at nine different levels over the last 45 years have been analyzed in this article, using the daily precipitation data from 1961 to 2005 in Ningxia. It has been found that the annual precipitation decreased at a mean rate of 3.6 mm/10 a. In the recent 15 years, precipitation obviously decreased in winter and spring; in summer and autumn, days of precipitation below 10.0 mm obviously decreased, but days of precipitation over 25.0 mm significantly increased. Differences in summer and yearly days of precipitation in 25.1-50.0 mm before and after 1986 were statistically significant at 5% and 1% level, respectively. The extreme trends of precipitation are obvious in Ningxia.

Key words: climate change, extreme event, frequency, precipitation, Ningxia