The new Bi2GaTaO7 compound was synthesized by solid-state reaction method and characterized by powder X-ray diffraction and the Rietveld structure refinement. The Bi2GaTaO7 compound crystallizes in the pyrochlore-type structure, cubic system with space group Fd3m and the lattice parameter a = 10.4516(5)A. The band gap of the Bi2GaTaO7 compound was estimated to be about 2.187eV. The Bi2GaTaO7 compound shows strong optical absorption in the visible light region (gimel > 420nm). This indicates that the Bi2GaTaO7 compound has the ability to respond to the wavelength of the 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 Bi2GaTaO7 compound was first investigated under ultraviolet light irradiation. MB was degraded largely after ultraviolet light irradiation for 70 min over the photocatalyst at room temperature in air. The high activity has potential to be kept in a wide range of wavelength up to 568 nm. (C) 2004 Elsevier B.V. All rights reserved.