Using Rotated Empirical Orthogonal Function (REOF) to analyze the annual variations of China dekad precipitation based on dekad precipitation data averaged over 1955-1998,the annual variations of the precipitation are divided into 6 categories which cover 8 regions geographically.The precipitation in each region is of regional characteristics,besides the common feature of more in summer and less in winter.The significant correlations between the precipitation in characteristic periods of time in different regions are considerable factors for mid- and long- term weather forecast.In recent 44 years,the trends of the precipitation in characteristic periods of time and annual precipitation in various regions are changing differently,but in some regions,the trend of the precipitation in characteristic period of time can respect that of annual precipitation.