The invention relates to a motor acceleration and deceleration control method and a three-dimensional pipette device. The motor acceleration and deceleration control method comprises the following steps: a target speed parameter and a target moving distance are acquired, and a target pulse number is obtained according to the target moving distance and a preset relation function; a motion control mode of a motor is acquired according to the target pulse number, the target speed parameter, a preset speed parameter array curve and a pulse number array curve; the current pulse number corresponding to motor operation is read; if the motion control mode contains a constant speed mode, the motor is controlled to be accelerated to the speed corresponding to the target speed parameter, operate constantly at the speed corresponding to the target speed parameter and finally be decelerated to operate to a preset lowest speed; if the motion control mode does not contain the constant speed mode, the motor is controlled to perform accelerated operation and then perform decelerated operation to the preset lowest speed. Therefore, the control way is simple, easy to implement and high in precision.