Manganese oxides nanomaterial (MnO x ) with crystalline phases of MnOOH nanorod and Mn 3 O 4 octahedron-like were synthesized by hydrothermal method based on the redox reaction between MnO 4 − and CH 2 O at 120°C and 200°C for 10h, respectively. The β-MnO 2 nanowires were prepared by calcining MnOOH nanorods at 300°C for 3h in air. Particles were characterized by XRD, FE-SEM, TEM, SA-ED, HR-TEM, Brunauer–Emmett–Teller (BET) and UV–vis diffuse reflectance spectroscopy. Their capability of catalytic degradation of alizarin yellow R with air oxygen in aqueous under visible light irradiation and electrochemical properties of as-prepared nanocrystal modified with carbon paste electrode were comparatively studied. The degradation products were determined by GC–MS. In addition, some influences factors, such as pH and temperature on the photocatalytic degradation were also investigated. Among the as-prepared MnO x nanostructures, β-MnO 2 nanowire exhibit higher specific capacitance and better catalytic activity than Mn 3 O 4 octahedron-like and MnO(OH) nanorod. The hydroxyl radical mechanism of the photocatalytic degradation of alizarin yellow R was detected and discussed.