The present invention relates to a power-off brake circuit for a DC fan, which comprises a control unit, a motor driver unit, a switch unit, a power-off protection unit, and a brake unit and a brake unit. The control unit is coupled to the motor driver unit, the switch unit, the power-off protection unit. The brake unit is coupled to the motor driver unit and the power-off protection unit. By means of the circuit design of the present invention, the independent brake loop is used to achieve the effects of power-off brake and of the accurate control of rotating speed is improved.