Abstract: Through statistic analysis of the data from1958 to 2000 in five stations of the Four Lake Watershed in Hubei Province,the characteristics and trend of precipitation were analyzed.The result showed that the regional differences of the precipitation among the region were not prominence.The seasonal distribution of the precipitation was asymmetrical,while the inter-annual standard deviation and coefficient of variation of the precipitation was 204.9 and 0.19 respectively.The precipitation during the summer and autumn accounted for 70.49 % of the annual precipitation.Used the Z index,the flood/drought status from 1958 to 2000 in the Four Lake Watershed was analyzed.The probability of flood and drought was almost equivalent with 25.58% and 27.91% respectively.The hydrologic-meteorological index and the modulus coefficient were used to analyze the trend of the wet and low water change of precipitation,of the continual ample water and low water,and their distribution features.The result showed that the precipitation in Four Lake Watershed existed three effectual durations of continual ample water and five effectual durations of continual low water from 1958 to 2000.

Key words: Characteristics of precipitation, Characteristics of precipitation, Runs theory, Preliminary analysis, Four Lake Watershed