A new optical frequency comb generation method has emerged using parameter four wave mixing in high quality factor Kerr micro-resonators. Due to the unique characteristics, it has broadened the application fields of the traditional solid state or nonlinear fiber femto-second laser based optical frequency combs, such as precise frequency calibration, precision spectroscopy, astronomy, waveform generation, optical storage and soliton transmission, telecommunication source and so on. In this paper, some principal theoretical modeling methods for Kerr micro-resonators based optical frequency combs are summarized and their inherent relationship is reviewed, then based on the nonlinear Lugiato-Lefever equation (LLE), a new stability analysis method is given to determine the modulation instability areas in both normal and anomalous dispersion resonators and hereby the different combs are classified. Finally the possibility of Kerr resonator with controllable feedback as an integrated multi-wavelength source is discussed and several different probably achieving methods and conditions are demonstrated.