A motor driving circuit adopts a motor driving chip provided with a speed control pin VTH and a minimum speed setting pin RMI. When the circuit is just started, charging characteristics of a first capacitor are utilized for enabling the voltage of the speed control pin to be maintained at a high level in a front charging period of the first capacitor, so that the motor is started at the minimum rotation speed in the period. Namely, the magnitude of current for starting the motor is low and a soft start function is achieved by using the motor driving circuit without the soft start function. Therefore, the cost is reduced. When the charging process of the first capacitor comes to an end, the voltage of the speed control pin descends gradually, so that the rotation speed of the motor increases gradually. The invention also discloses a motor driving method and a fan.