Bayesian classics,especially the collection of Sanskrit Bayeux manuscripts in the Tibet Museum,have high academic value and potential for international social science and South Asian cultural research.They are important historical,cultural and academic materials for the study of Sino-Indian cultural exchanges between the Indian Sanskrit culture and Chinese cultures,and the Indian Sanskrit cultures impact on traditional Tibetan and Chinese mainland culture.A layer of white power was found to cover the Bayeuxs script,which obscured the characters. Is it mildew or contamination? To better protect this precious cultural heritage,three-dimensional video microscopy and Fourier transform infrared spectrometer were used to analyze the “white powder” appearring in the Bayeux manuscript.Results show that the white powder is kaolin,which was added during the manufacturing process to prevent pages from sticking to each other.The same results were found on “Bhagavad Gita and its notation” and on Bayeux classic No.0738.The white power was found to be porcelain clay powder.The research provides scientific results for conservation of Bayeux classic manuscripts.