Abstract：Recently, the direct methanol fuel cell (DMFC) has been drawing an increasing attention of researchers to the power applications of advanced portable electronics, because of its advantages such as high theoretical power density, good efficiency, relatively simple system features and convenience in use. The design of its flow field is one of key factors for DMFC performance. In this paper, a non-equipotent flow field, with the channel width being gradually changed along the channel length, is designed. Transparent DMFCs with different flow fields are designed and fabricated. The performance of DMFC with a non-equipotent serpentine flow field is compared to that with the equipotent serpentine flow field. And the performance of DMFCs placed in the horizontal and vertical directions is compared. Results show that the power difference between the DMFC with the non-equipotent serpentine flow field and that with the equipotent serpentine flow field is enlarged with the increase of the fuel cell current. The absolute peak power of the DMFC with the non-equipotent serpentine flow field, placed in the horizontal direction, is about 33% higher than that with the equipotent serpentine flow field. It is also found that the performance of the DMFC with the equipotent serpentine flow field is improved significantly while being placed in the horizontal direction as compared to that in the vertical direction. But the performances of the DMFC with the non-equipotent serpentine flow field are almost the same when it is placed in either directions.