In order to develop a dye coloring technology on Conchiolin layer in cultured pearls, appropriate dyes were selected, their solubilities in various solvents were studied, and adsorption and desorption experiments were performed. Solubilities of several basic dyes known to suitable for the pearl coloring, i.e., Rhodamine 6G(R6), Rhodamine B(RB) and Methylene Blue(MB), in several solvents (distilled water, methanol, ethanol, and acetone) were investigated. Among these dyes, R6 was chosen as a dye for single component adsorption and desorption experiment due to the relatively good solubility in various solvents tested. Solubilities of dyes were judged to be enough to color the pearls since dye concentrations in pearl coloring are, in general, not so high. The internal surface area of the pearl layer is believed to be directly related to the dye adsorption; the single-point internal surface area of the pearl layer measured at the nitrogen relative pressure of 0.3 was found to be 0.913㎡/g, and the BET internal surface area, 1.01㎡/g. The most probable diameters of micropores and macropores were found to be 40Å and 5000Å, repectively, from the pore size distribution d/ata. Adsorption isotherm was well fitted to the Langmuir isotherm model, resulting in q=1.62C/1+1.09C˙