The utility model discloses a brush is thrown and is moved back controlling means, including collecting ring, conducting ring, brush holder and brush, the brush is located between collecting ring and the conducting ring, include still that brush electric current and state sensor, brush are thrown to move back actuating mechanism and brush and throw and move back the controller, on the brush was located to brush electric current and state sensor, the output and the brush of brush electric current and state sensor were thrown the input that moves back the controller and are linked to each other, and the brush is thrown the output that moves back the controller and brush and is thrown and move back actuating mechanism and link to each other, and the brush is thrown and is moved back actuating mechanism and link to each other with the brush. The utility model discloses brush is thrown and is moved back controlling means throws and moves back brush that actuating mechanism come to make dropped into and work all the time under the preferred current density state through setting up the brush, prevents the heavy wear of brush, makes the motor more automatic.