The study investigates Sanskrit-Chinese transliterations. The materials of the study are the Chinese transliteration of the Heart Sutra in the Dunhuang manuscripts. Up to the present, the phonetic phenomenon of the manuscripts have not been dealt with yet. Liang qichao (1920) considered that there were three periods in the interpretation of the Buddhist Scriptures. The materials of the study are belonged to the third period (between Zhenguan and Zhenyuan in Tang Dynasty), that is to say, the period of new interpretation. It is belonged to the range of the Ancient Chinese sound in Chinese historical linguistics. The study attempts to handle some questions by way of the contrastive linguistics and the style of words, including the authorship, transliterating Sanskrit with two types of the voiced stops, the phenomenon of devoicing in Chinese, whether the labials being polarized or not, and trying to recognize the source and change of the special initials mb-, nd-, ng-. By the research, it's possible to understand some representations of the dialect in Tang Dynasty, and to provide another materials of studying the Ancient Chinese sound.
