The invention discloses a power amplifier circuit comprising a digital potentiometer which comprises a temperature sensor, a memory, and a variable resistance, wherein the corresponding information oftemperature data and variable resistance value is kept in the memory; the variable resistance is connected with the bias circuit, controlling the linear, the efficiency, and the gain of the power amplifier circuit. The invention also discloses an initializing method for the power amplifier circuit, comprising variable resistance value in digital potentiometer when different temperature record makes the linear, the efficiency, and the gain of the circuit reach a good index. The invention also discloses a power amplifying method for power amplifier circuit, changing variable resistance value according to the temperature information collected by temperature sensor and regulating the power control circuit to keep good linear, efficiency, and gain under different temperature.