In this paper, a novel dual-frequency impedance converter is proposed, and a rigorous derivation process is given. Based on this, a 0.61/2.6 GHz dual-frequency and high-efficiency power amplifier is designed. The joint simulation results show that the designed power amplifier achieves a maximum power added efficiency (PAE) of 68.3% at 0.61 GHz and achieves a saturated output of 41.53 dBm; At 2.6 GHz, the saturated output power is 40.8b dBm, and the maximum PAE is 56.3%. The designed dual-frequency power amplifier has good working performance.