Abstract: In order to solve the problem of increasingly tight spectrum resources in the 5G wireless communication system, a novel dual-band reconfigurable circuit structure is proposed. This structure uses PIN switchs to control the working state of the branch in the output matching, and completes the switching of different working bands. Then, the input matching is designed based on the wideband filter theory, and a good matching within 1.5−4.5 GHz is achieved. Using the LC resonance theory and π equivalent, the lumped circuit is converted into a distributed circuit so that the circuit is optimized at high frequency. A reconfigurable power amplifier which partly covers the L, S and C bands is designed and manufactured. The test results show that output power is greater than 39.5 dBm and PAE is higher than 39.5% at 1.50−2.85 GHz, output power is greater than 38.1 dBm and PAE is greater than 43.5% at 3.15−4.50 GHz. The test results meet the design requirements and verify the correctness of the theory. This structure combines the advantages of reconfigurable and broadband technology which is of great significance to the future development of wireless communication systems.