The surface features of CsTeMoO₆ with β-pyrochlore structure have been investigated during adsorption and photocatalytic oxidation of methylene dye under visible light irradiation. The apparent quantum yields are 5.12•10⁻⁶ and 3.57•10⁻⁶ molecules/photons for MB and MO conversion. The refinement of the CsTeMoO₆ electronic structure has been carried out by both transmittance and reflectance spectroscopy. The impurity defect absorbance bands in the visible light region have been found out into the wide band gap. Superoxide radicals have been detected as the main active radical species for oxidation, whereas hydroxyl radicals are not formed because of specific holes reaction. Features of surface interactions with cationic and anionic dyes have been studied. The abnormal high absorption capacity of methylene blue by CsTeMoO₆ has been obtained. Cs atoms play important role for cationic dye oxidation, while anionic dye predominantly adsorbs and decomposes on the Te/Mo-atom surface centers. The phase stability and composition of catalyst powder have been confirmed by X-ray powder diffraction analysis and X-ray microanalysis. The surface composition and features have been investigated using X-ray photoelectron spectroscopy.