Flow field has a great impact on the performance of a PEMFC (proton exchange membrane fuel cell) and lots of research works focus on the design of channels. In this paper, a novel 3D cathode flow field with main and sub-channels and transition areas is presented and evaluation criteria for the guidance of flow field design are also put forward. Results show that performance evaluation criterion and effective mass transfer coefficient can be used to evaluate the performance of a PEMFC. Therefore, the evaluation criteria above are suitable for the guidance of design for the flow field. A PEMFC with the 3D cathode flow field performs much better than a PEMFC with conventional parallel straight cathode flow fields. Porous ribs on the bottom help to improve the performance of the 3D cathode flow field. (C) 2018 Elsevier Ltd. All rights reserved.