Abstract: A power amplifier includes a current generating circuit, a first mirroring circuit, a power amplifying circuit and a stacked circuit, in which the current generating circuit is configured to output a first current according to a received first control voltage; the first mirroring circuit is configured to, according to the first current, minor the current and output a first bias current, the first bias current for being input into the power amplifying circuit; and the power amplifying circuit is configured to, according to a first radio frequency signal and the first bias current, output a second radio frequency signal with a power that meets a preset condition.