A hierarchical porous structure of MnO2 nanosheet arrays is synthesized on three-dimensional surface of carbon fiber paper (CFP). As-synthesized MnO2/CFP is thoroughly characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The direct deposition of MnO2 enables a good electrical connection to the CFP, and thus eliminates the need for polymeric binders and carbon additives. Moreover, the unique structure with a large surface area enables efficient and rapid ion and electron transfer in electrochemical processes. When testing as an electrode for supercapacitors, the MnO2/CFP shows a specific capacitance (204F/g), rate capability (75% retention), and good cycling life (~100% retention after 1000cycles).