It is disclosed a wireless power supplying system and an self adaptive adjustment method thereof. The method includes: a step for detecting an operating status of an electric power sending unit and determining, based on the detected operating status, whether the electric power transmitting unit satisfies a condition of a normal operation of the system and a step for determining, based on the above determination result, whether to adjust a master frequency of an oscillating circuit so that the master frequency of the oscillating circuit is between a resonance frequency of a transmitting coil and a resonance frequency of a receiving coil. The master frequency of the oscillating circuit is adjusted automatically, so that the master frequency is always close to the resonance frequency of the transmitting coil and that of the receiving coil, thereby maintaining stably the power output of the system.