A power amplifier, a radio remote unit (RRU), and a base station, where the power amplifier includes an envelope controller, a main power amplifier, and an auxiliary power amplifier. The main power amplifier and the auxiliary power amplifier both set an envelope voltage output by the envelope modulator as operating voltages, and because the operating voltages of the main power amplifier and the auxiliary power amplifier may be adjusted simultaneously, symmetry of the power amplifier is improved, and an efficiency loss occurring probability is low, thereby enhancing efficiency of the power amplifier.