Brief introduction of wavelet analysis and its application in atmospheric science is presented and the periodicity of 41 years (1960 to 2000) in the Chongqing precipitation time series (single station data) was diagnosed by the means of one-dimension Morlet wavelet transformation. The results show that there exists an obvious quasi 18-year period oscillation in Chongqing rainfall and less pronounced periods of 11, 3-5 and 8 years. It is found that the zero points of Morlet wavelet transformation coefficients correspond with the inflexions of the 40-year precipitation variation in Chongqing, and the zero-point positions of the of Morlet wavelet transformation coefficients correspond with the positions of the abrupt change points of the precipitation variation in Chongqing. Either over a large time scale or small scale, for summer and annual precipitation variations, Chongqing was in an obviously more-than-normal period, while for autumn precipitation, in an obviously less-than-normal period.