Based on the flood season(from June to September) precipitation data from 19 climatic stations within the Fenhe River Basin from 1959 to 2007,and using wavelet transform method,Mann-Kendall and other statistical methods,a time series analysis was made on the precipitation.The results showed that the precipitation in flood season in the Fenhe River basin showed a declining from 1959 to 2007,with an average velocity of-9.79 mm/10 a.However,the precipitation in June increased with a rate of 2.79 mm/10 a,while it decreased with a rate of-6.54,-2.69,-3.36 mm /10 a respectively in July,August and September.This indicated that the precipitation decreased in July and September was the main source of precipitation reduction in flood season.An abrupt change in the flood season precipitation appeared after 1978 when the basin underwent a period of little rain.From 1959 to 2007,there existed 8 to 15 years and 3 to 7 years cycles of precipitation series in flood season and the significant time-scale change were 2,5,10 and 12 year.But the 5 year scale was the main cycle because its oscillation was most strongly.According to the trend of the wavelet transform result,it can be estimated that there will more precipitation in flood season in the near future in the Fenhe River basin.