Disclosed herein is a power amplifier system including: a power amplifier; a power controlling unit providing driving voltage and driving current corresponding to a preset reference voltage to the power amplifier; a current controlling unit performing a control so that control current corresponding to applied control voltage flows; a bias controlling unit detecting current and voltage corresponding to the driving current of the power controlling unit and controlling bias current of the power amplifier according to the detected voltage; and a current adjusting unit detecting bias voltage corresponding to the bias current of the power amplifier and adjusting the driving current of the power controlling unit according to the detected bias voltage. Even though applied control voltage increases, current applied to the power amplifier is appropriately adjusted, thereby making it possible to improve characteristics of the power amplifier.