The invention discloses a motor precise control device. The motor precise control device comprises a motor, a Hall sensor, a rotary disc, a micro-control unit, a control circuit board, a power source and multiple magnets. The control circuit board is electrically connected between the power source and the motor. The control circuit board comprises a power source input control unit and a brake control unit. The power source input control unit, the brake control unit and the Hall sensor are electrically connected with corresponding input/output ports of the micro-control unit respectively. The Hall sensor senses the magnets on the rotary disc and outputs pulse signals to the micro-control unit. The power source input control unit is used for controlling connection and disconnection between the power source and the motor. The brake control unit is used for rapidly reducing voltage across the two ends of the motor to 0 V. The invention further discloses an automatic milk brewing machine adopting the motor precise control device and a powder outlet control method of the automatic milk brewing machine. The precision of the motor control device can be improved, and then the powder outlet precision of the automatic milk brewing machine is improved.