In order to meet the requirements of high efficiency and broadband for the wireless communication system, a high efficiency and broadband gallium nitride power amplifier is designed and verified. Using the step-matching structure, the bandwidth has been improved. Furthermore, the input matching network is constructed by connecting several microband lines serially to reduce the matching Q value. Meanwhile, the harmonic control network is designed as the output matching network, which is built by a quarter-wave (λ/4) line open circuit and short circuit microwave lines in parallel. Thus, its drain efficiency can be improved. This design is simulated and tested at 2.2-3 GHz . After measuring, it attains an output power of 39.5-41.5 dBm, Gain of 10.5-12.5 dB with drain efficiency of 65.1%-78.3% and power added efficiency of 64.8%-76.2%.