Thai Jasmine rice is the main export rice product of Thailand. It grows mainly in the central part of Thailand where fluctuation of rain, humidity and heat can be expected. These variation could cause grain chalkiness which is an unpleasant trait adversely affecting appearance and milling quality of rice. The chalkiness part causes from packing of carbohydrate non-uniformly in the grain. Chalkiness affect the quality and the price of rice directly. To categorize the rice grain chalkiness, the effective tool has not yet been implemented to be used widely in Thailand. Mostly, human detection has been carried out to classify the grain quality. Here we present the investigation of UV-VIS spectroscopy, SEM analysis of grain chalkiness from rice sample obtained from Department of Rice, Ministry of Agriculture of Thailand. Investigation.  Rice grain with chalkiness level of 1 to 5 were investigated. Absorption peak intensity of 532 nm was observed varying depending on the grain level of chalkiness. Thus, we fabricated chalkiness detection tool using light of wavelength 532 nm incident onto rice grain and detect the transmission with photodetector and CCD camera. The transmission result was calculated to identify the level of chalkiness together with image processing analysis to ensure high precision of chalkiness classification. This work was supported by Kasetsart University Research and Development Institute (KURDI).