A power amplifier system with power control function provides accurate and efficient power control by controlling a bias voltage and a bias current of the power amplifier at the same time. A power amplifier system with power control function according to an aspect of the invention may include: a power amplifier receiving a bias voltage and a bias current from a power voltage source and having a gain controlled according to the magnitude of the bias voltage and the bias current; a voltage detection controller detecting the magnitude of the bias voltage being supplied to the power amplifier and comparing the magnitude of the bias voltage with a predetermined reference voltage to control the magnitude of the bias voltage; and a current detection controller detecting voltage having a magnitude equivalent to the magnitude of the bias current being supplied to the power amplifier and comparing the magnitude of the voltage equivalent to the magnitude of the bias current with the reference voltage to control the magnitude of the bias current.