On the basis of partial decomposition in frequency domain with harmonic wavelet package method and Hilbert demodulation， the demodulation based on harmonic wavelet package transform is introduced. The Fourier spectra analysis is carried out after preprocessing， and the depth of decomposition and frequency band are determined by the analysis of frequency band distribution and the theoretic computation of gear box characteristic frequency. Then with FFT and IFFT the corresponding meshing component is extracted. Finally， the modulation information is extracted via Hilbert envelop analysis approach. With the proposed method， wear and notch faulty gearbox are tested and analyzed by experiment， respectively. The results prove that this method can locate gearbox fault precisely and provide corresponding basis for judging fault cause and degree.