The flow channel structure at the cathode side is one of the main factors affecting the performance of proton exchange membrane fuel cells. The flow channel at the cathode side needs to discharge liquid water out of the fuel cell in time and make oxygen flow to the cathode catalytic layer as much as possible. Thus, the phenomenon of cathode flooding and concentration polarization is avoided. An innovative 3D cathode side channel, sugar gourd type channel, is designed. The sugar gourd type channel is formed by adding arc-shaped side trapezoidal block based on the traditional straight flow channel. The simulation results show that, compared with the traditional straight flow channel, the current density in the high current density region is increased by about 8%. And because of the special structure of the sugar gourd type channel, the air flow advances to the outlet in the form of pulse decline, and the heat and mass transfer are significantly enhanced. In addition, the influence of arc-shaped side trapezoidal height on overall performance is further explored.