A single-shot measurement and analysis technique with a Fourier transform limited pulse as a reference pulse was presented, which can be used for measuring the complex picoseconds pulses. Substituting the Fourier transform with a short time Fourier transform, a time-frequency analysis of the spectral fringe was achieved to directly extract the chirp characteristics or composition of complex pulse. Furthermore, the temporal envelope of pulse was reconstructed from the spectrogram by summing the power density S(ω,t) along the spectrum ω axis. To verify the utility of this method, this method and the traditional spectral interferometry was used to measure a linear chirped pulse and a complex pulse respectively. The results show that this method can be used to measure the characterization of complex shaped pulses in real-time, and with a temporal resolution of 70 fs.