A new enhanced drainage parallel (EDP) flow field was designed that not only enhances under-rib convection but also enables a more uniform distribution of hydrogen and oxygen. Through the optimization of the model, we established the influence of the flow field size, relative humidity, and stoichiometric ratio on cell performance. When the rib width is reduced, the maximum power density is improved. Compared with the parallel flow field and serpentine flow field, the maximum power density of the EDP flow field was increased by 69.4% and 7.9%, respectively. Under optimal conditions, the net power of the EDP flow field can reach 0.56 W/cm2. In the single-cell test, the maximum power density of the EDP flow field can reach 1.19 W/cm2. This implies that the EDP flow field has potential application of proton exchange membrane fuel cells.