Abstract: Using the temporal wavelet transform method for three-dimensional data,the characteristic timescales and temporal-spatial changes of interannual variability of the subtropical high over the northern Pacific in summer are investigated.The results show that there are 2-year,5-year and larger characteristic timescales for interannual variability of the subtropical high.The largest amplitude energy centers corresponding to the 2-year and 5-year characteristic timescales are located at the(27.5癗,135癊)and(35癗,167.5癊)respectively.The longitudinal evolutions of the largest centers in association with the characteristic timescales appear obviously longitudinal oscillations.The latitudinal evolutions of the largest centers in association with the characteristic timescales appear obviously periodicity and the smaller amplitude latitudinal oscillations.In the longer time changes,the location of the largest amplitude energy center corresponding to the 5-year characteristic timescale has a tendency to move towards the south.