Maximal overlap discrete wavelet packet transform (MODWPT) is introduced and the Hilbert spectrum based on MODWPT is applied to nonstationary signal processin g. MODWPT could decompose the complicated multicomponent signal into a number of single components whose instantaneous frequency and instantaneous amplitude o w n physical meaning. Furthermore, the complete time frequency distribution of co mplicated signal can be obtained after the instantaneous frequency and instantan eous amplitude of each single component are calculated. The analysis results fro m different kinds of non stationary signals show that the Hilbert spectrum base d on MODWPT could analysize nonstationary signals effectively and is superior to that based on empirical mode decomposition (EMD).