The performance of a proton exchange membrane fuel cell is affected by the flow field structure. Improving the flow field is a low-cost method for improving the power of proton exchange membrane fuel cells. This study proposed a new tapered-slope serpentine flow field and studied its performance through visualization experiments and numerical simulations. The results show that compared with conventional serpentine flow field, the tapered-slope serpentine flow field had a uniform distribution of hydrogen and oxygen concentration in the downstream, the pressure drop was reduced by 58.4%, and the maximum power density was increased by 3.75%. The visualization experiments results show that the guiding structure and slope design of U-shaped corner of the tapered-slope serpentine flow field maintained the shape of droplets, limited the splash of droplets when passing a U-shaped corner, and avoided the breakage caused by droplets colliding with the channel wall, the drainage process time is 62.3% less than conventional serpentine flow field. The experimental results of different reaction inlet flow rates found that tapered-slope serpentine flow field has good drainage performance and improves mass transfer. Increasing the flow rates can make the performance of conventional serpentine flow field close to the tapered-slope serpentine flow field.