The Ga2BiTaO7 compound was synthesized by solid-state reaction method and characterized by powder X-ray diffraction method and the Rietveld structure refinement. This compound crystallizes in the pyrochlore-type structure, cubic system with space group Fd3m and the lattice parameter a = 10.4544(2) Angstrom. The band gap of the Ga2BiTaO7 compound was estimated to be about 2.47(1) eV. It shows strong optical absorption in the visible light region (lambda > 420 nm). This indicates that the Ga2BiTaO7 compound has the ability to respond to wavelength of visible light region and has potential for splitting water into H-2 and O-2 under visible light irradiation. Photocatalytic degradation of methylene blue (MB) dye on the Ga2BiTaO7 compound was first investigated under ultraviolet light and visible light irradiation. MB was obviously degraded after visible light irradiation for 140 min with the photocatalyst at room temperature in air. The high activity has potential to be kept in a wide range of wavelength up to 505 nm. (c) 2005 Springer Science + Business Media, Inc.