The invention discloses a voltage regulation circuit, a voltage regulation device and a voltage regulation method. The voltage regulation circuit comprises a transformer, a step-up unit and a step-down unit, wherein the step-up unit and the step-down unit are electrically connected with the transformer; the primary-side winding of the transformer is accessed to a first voltage, and the secondary-side winding outputs a sensing voltage of the first voltage; the step-up unit is used for controlling the first voltage and the forward sensing voltage to be serially outputted; and the step-down unit is used for controlling the first voltage and the backward sensing voltage to be serially outputted. Through forward connection or backward connection with the secondary-side winding of the transformer, the input voltage is serially connected with the positive/negative sensing voltage, the output voltage is thus raised or reduced, and requirements on the transformer are reduced.