The present invention generally relates to a structure and method of audio amplifier with power feedback, including a power amplifying unit, a loud-speaker, a current sensing unit, a voltage sensing unit and a multiplying unit. The power amplifying unit includes an input side and an output side, the input side inputs an audio voltage signal, and the loudspeaker is electrically connected to an output side of the power amplifying unit. The current sensing unit is electrically connected to the output side of the power amplifying unit and senses the output current of the power amplifying unit and then converts it into a current control voltage signal. The voltage sensing unit is electrically connected to the output side of the power amplifying unit, and senses the output voltage of the power amplifying unit to form an output sensing voltage signal. The multiplying unit obtains the voltage of the current control voltage multiplied by the output sensing voltage, and the output side of the multiplying unit is electrically connected to the input side of the power amplifying unit to form a closed loop power feedback structure. Accordingly, the output quality of the amplifier and loud-speaker is improved.