Abstract: This paper reveals that the periodic oscillation performs in 3-4 years and quasi-two years between the sea temperature on the equatorial East Pacific and the rainfall in the lower reaches of the Yangtze River,using maximal entropy spectral analysis method.Moreover,it is found that both mentioned above have the obvious correlation passing the time delay correlation analysis.It is most obvious that the sea temperature has the positive correlation with the rainfall delaying four-month.Furthermore,a multiple-stage numerical filter is used for the both departure sequence month by month to conduct high-pass,low-pass and band-pass filter.And it has conducted the time delay correlation analysis for the both at the different time scales.