Abstract: Rubber wood purified cellulose fibrils(PCF) were prepared by chemical treatment. Cellulose nanofibrils(CNF) was obtained by high-speed shearing followed by ultrasonication. Manganese dioxide(MnO₂) nanosheet was prepared by one-way synthesis method. Flexible electrode materials were prepared by vacuum filtration using CNF as structural support, MnO₂ and carbon nanotubes(CNTs) as active electrode materials. The structure and properties of CNF, MnO₂ and electrode materials were characterized by various means, and the electrochemical properties of the prepared electrode materials were characterized. The results showed that the diameter of CNF was 3-10 nm. The obtained CNF had a large aspect ratio and could be utilized as a good structural substrate. Additionally, CNF had typical cellulose type I structure. The MnO₂ nanosheets had petal-like structure with a crystal form of δ. The results of electrochemical performance showed that the specific capacitances at the scan rate of 50 mV/s and the current density of 0.1 A/g were 78.45 and 97.02 F/g, respectively. In the low frequency region, the slope of the straight part of the electrochemical impedance spectroscopy(EIS) was large, which indicated that the electrode material had good capacitance characteristics. The capacitance retention of the electrode material was always maintained at about 99% during the 200 charge and discharge cycle test. The results showed that the electrode material had good electrochemical properties and certain flexibility, and can be used as an electrode material for supercapacitors.