The claret membrane, instead of the purple membrane, was isolated when the conventional method for isolating purple membrane from Halobacterium halobium was applied to Halobacterium sp. XZ515. The SDS-PAGE results showed that only one protein, archaerhodopsin, existed in claret membrane with M. W. similar to BR. The method for isolating and purifying the archaerhodopsin, an intrinsic membrane protein, by detergent dissolution and hydrophobic chromatography on the column of octylsepharose, was also introduced. The pure archaerhodopsin showed the absorption spectrum similar to BR and was able to produce the M412 photoproduct in the photocycle under illumilation. It was concluded that this archaerhodopsin was a BR-like retinal protein.