Cryptomelane nanomaterials were synthesized by a facile redox reflux method. The physicochemical properties of these composites were studied in detail using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, laser Raman spectroscopy, thermogravimetric analysis (TGA), and N-2 adsorption-desorption techniques. The catalytic activities of nanocryptomelane were evaluated through treatment of aqueous solutions that contained basic fuchsin. In the case of basic fuchsin, the catalytic activity of synthetic nanocryptomelane was much higher than that of natural cryptomelane. Moreover, synthetic nanocryptomelane shows high stability and recyclability, has a high specific surface area, and is rich in mesopores. It could be anticipated that the specific surface area of the material had ar. obvious effect on the degradation of basic fuchsin. Kinetic studies indicated that the reaction follows the Langmuir-Hinshelwood model. The catalytic activities were found to be primarily correlated with the specific surface area. Overall, cryptomelane nanomaterials have great potential in the treatment of dye-containing wastewater.