Abstract: Based on the wavelet analysis method,study is made of SST long term variation over Indian Pacific ocean,and the interdecadal variation of SST distribution over the study area is discussed in detail with variance analysis method.The results show that the SST long term variation over equatorial east Pacific displayed the QBO,3-7y(LFO),10-12y,18-20y and 30-40y with interdecadal variation in these oscillations.These oscillation are not well distributed during the recent half of century.The distribution of these oscillation modes is difference over different SST interdecadal background.