Touching upon that the crack fault of the rotor may occur after the RCP has operated a long time, the fault feature can be identified effectively by the method of the wavelet analysis. Based on the simulation signal of the vibration model of the RCP cracked rotor and the method of CWT, the cross-correlation coefficients between the fault signal and the different wavelet basis which are selected from the wavelet basis library can be computed. After confirming the maximum of the cross-correlation coefficients, the optimal wavelet basis applied to the fault signal of the cracked rotor will be found. And the three-dimensional diagram which covers the power spectrum, the scale of transform and the frequency will be described, once the signal analysis of the fault is completed by use of the optimal wavelet basis. The results of simulation illustrate that the wavelet basis selected by the maximum cross-correlation coefficients can become the optimal wavelet basis, and the fault feature of the cracked rotor can be recognized effectively.