The invention discloses a powder sample adding device and a powder sample adding method. The method comprises the following steps: a pressure rod connected with a vertical slide table downward vertically rotates under the driving of a stepping motor and a direct current motor; an automatic powder sample adding head on a horizontal slide table slides to a position just below the pressure rod underthe driving of the stepping motor; the pressure rod downward vertically rotates to the core of the automatic powder sample adding head, powder in the automatic powder sample adding head flows out to aprecision balance, and the precision balance measures the mass of the added powder; a controller reads the mass value fed back by the precision balance in real time and compares with the mass value with a preset target value, and when the mass value equals to the target value, sample addition is exited, and the controller controls the pressure rod to rapidly inversely rotate; and the controller calculates the real-time powder sample adding speed according to the mass value which is fed back in real time, compares the speed with a preset speed value, and controls the rotating speed of the coreof the automatic powder sample adding head according to the comparison result in order to control the sample adding speed to reach the preset value. When the device or the method is adopted to add apowder sample, the working efficiency is high and the error rate is low.