A　dual-band　power　amplifier　(PA)　which　operates　at　two　specific　frequencies　of　1.8GHz　and　2.0GHz　simultaneously　is　designed.　The　input　matching　circuit　has　one　access　with　a　special　matching　network　which　resonates　at　two　frequencies.　The　output　matching　circuit　is　the　simple　L-type　matching　network　and　was　designed　under　the　guide　of　load-pull　methodology.　The　simulated　results　show　that,　at　the　two　frequencies,　the　S21　achieves　12.63dB　and　13.64dB　respectively,　the　S11　reaches　-11.88dB　and　-10.76dB.　The　1-dB　power　compressions　of　the　two　frequencies　both　achieve　6　dBm　and　the　power　gain　achieves　10dB.