The Japanese banana cloth, constructed out of <i>Musa liukiuensis</i> fibers, is one of the traditional woven cloths in Okinawa. The dyeing properties and microstructure of <i>Musa liukiuensis</i> fibers are investigated using the colorant of <i>Raphiolepis umbellata</i> grown in Okinawa. Conclusions relate to conditions for colorant extraction, dye uptake, and color fixing by chrome and copper mordanting. <i>Musa liukiuensis</i> can be conserved by replacing repeated dyeings with copper mordanting.