A diagnosis method using wavelet packet, frequency band energy analysis and envelope analysis was presented for the rolling bearing fault diagnos is. Firstly, vibration signal of rolling bearing was decomposed at different leve ls by wavelet packet. Then, energy of each frequency band was calculated. According to the change of frequency band energy, fault frequency band of the rolling bearing was found. Finally, the reconstructed signal of fault frequency band was analyzed by using envelope spectrum. By contrasting the frequency on spectrum peak with the fault feature frequency, the fault type of the rolling bearing was identified. Results from the experimental vibration signal analysis show that the proposed method is effective in diagnosing the rolling bearing faults.