The invention discloses a method and a system for improving wireless energy transmission efficiency by using a feedback tuning method. The system comprises a phase-locked loop oscillating circuit, a drive amplifying circuit, a transmitting resonant circuit, a current extracting circuit, a receiving and tuning circuit, a rectifying and filtering circuit and a digital control circuit. The method comprises the following steps of: transmitting the output frequency of the oscillating circuit at the transmitting end and locking the frequency on the oscillation frequency of the transmitting resonantcircuit in a phase-locked loop way; controlling the resonant frequency of the receiving and tuning circuit at the receiving end in a digital feedback way according to the output of the rectifying andfiltering circuit; and coupling the transmitting end and the receiving end by a magnetic field. The output frequency of the phase-locked loop oscillating circuit and the resonant frequency of the receiving and tuning circuit are self-adaptively tuned on the resonant frequency of the transmitting resonant circuit, thereby improving the voltage output frequency of a wireless energy transmission system.