Waveguide bandpass filter is an important component of high-power microwave filtering, which provides the possibility of high-power microwave transmission for 5G communication base stations. Based on the frequency band gap characteristics of photonic crystals, a two-dimensional cylindrical photonic crystal is introduced into the rectangular waveguide, and a two-dimensional cylindrical photonic crystal waveguide bandpass filter for 5G communication is designed. The filtering characteristics of the filter is simulated and studied. Furthermore, the characteristics and performance changes of the filter are also presented when point defects and line defects are introduced. The two-dimensional photonic crystal structure exhibits bandpass characteristics between 3 GHz and 7 GHz in the rectangular waveguide. The simulation results show that the filter can be applied to the n77, n78, and n79 frequency bands of 5G communication.