Abstract: The shape, the photobleaching, and the thermo- stability of red monascus pigment absorbed by potato starch were investigated. The strong absorption effect of potato starch on monascus pigment was confirmed by the changes of absorbance value. The optical microscopy experimental results indicated that the red monascus pigment were embed on the surface of potato starch granules,and the typical polarization cross of starch was not obviously changed by the red monascus pigment layer. Under illuminated by the sunlight,6 months,the great changes of photoluminescence intensity were caused by the photobleaching of red monascus pigment. Under steamed at 100℃,only small amounts of red pigments were decomposed.