Layered Aurivillius compound Bi5Ti3CrO15 has been synthesized by a hydrothermal method for the appli-cation as a photocatalyst to liberate hydrogen from water.Bi5Ti3CrO15 owns a narrow band gap(Eg～2.46 eV)and shows stable photocatalytic activity under both full range(λ≥250 nm)and visible light illumination(λ≥420 nm).A short hydrothermal reaction time is critical to achieve high photocatalytic activity as defects such as Cr6+and Bi5+can be avoided.An AQE as high as 3.66％at 420 nm±20 nm has been recorded,warranting promising application in the field of solar energy conversions.DFT calcu-lation reveals the important role of Cr3+cations for visible light sensitivity of Bi5Ti3CrO15.