Micro direct methanol fuel cell (DMFC) is a good candidate for portable applications, due to its high energy density, low pollution, simpler and safer handling. Micro electromechanical system (MEMS) technology shows the advantages of high resolution, high reproducibility, micro-scale fabrication, and flexible, convenient process, which could provide a technical support for the miniaturization of a DMFC. The type and size of flow field with capillary network structure. Three-dimensional computational simulation will be employed to assist the design and optimization of the flow field structure, and the simulated results will be experimentally compared with the performance of DMFC based on MEMS fabrication. The mechanism of mass transport and heat conduction in micro-scale will be evaluated. Research emphasis will focus on the relationship between the micro structure of flow field and the DMFC performance so that the power density of a DMFC could be improved. It is expected that the work will help the utilization of the novel flow field and the understanding of the relationship between flow field structure and its performance will be established.