The invention discloses a radio frequency output circuit with tunable power. The circuit comprises a radio frequency source transformer, wherein one output port of the radio frequency source transformer is connected with a gate of a power amplifier module. The circuit is characterized by that the other end of the radio frequency source transformer is connected with a gate bias voltage control circuit; the source of the power amplifier module is grounded; the gate of the power amplifier module is connected with a grounding resistor; the drain of the power amplifier module is connected with a fixed voltage direct current power source; and the drain of power amplifier module is connected with a radio frequency filter network, thereby externally outputting radio frequency power through the network.