In the paper, several frequently-used real and complex wavelets are investigated using time series of the Nino3 sea surface temperature (Nino3 SST, 18711996; 5oS5oN, 90o150oW), to supply the idea of wavelet choosing. It is found that with an increasing vanishing moment there is a narrower time domain and higher time resolution with bigger amplitude of wavelet, while the frequency resolution is in contrary to the time domain wavelet. The complex Morlet wavelet has an excellent frequency resolution. And Mexican hat wavelet, which is the second derivative of Gauss function, has a good time resolution. In addition, compared with total wavelet power, the power of the real or imaginary part of wavelet can significantly improve time resolution while it does not affect frequency resolution.