In the light of the extraction of drilling process features of vibration signal from background noise, a new method is developed to enhance the signal feature by the wavelet packet division-spectral subtraction. At first, the machine’s idling signal is regarded as the“additive noise”of the monitoring signal according to the principle of classical spectral subtraction. Then, the“additive noise”and monitoring signal are divided into multiple sub-bands by the wavelet packet spectrum subtraction on the basis of the characteristics of vibration signal in the drilling process. Finally, the frequency spectrum of“additive noise”is subtracted from the corresponding sub-bands, and the vibration signal is reconstructed to enhance the drilling process feature. Simulations and experimental results show that the method can be used to enhance drilling process features of the monitoring vibration signal, to reduce the influence of background noise and to establish the mapping model between drilling process and monitoring signal.