The Periplus of the Erythraean Sea as one of the Periplus series of ancient Greek-Roman，was written by the anonymous Greek from Egypt in the middle of the 1st century based on his navigation and trade experience in the Indian Ocean. Its two manuscripts respectively collected in Heidelberg University and British Museum. As the only surviving work about the direct knowledge of the Indian Ocean in the early Greek-Roman world，it provides the most complete and authoritative record of the navigation and trade in the Ancient Indian Ocean. It is of great value to study the early Indian Ocean trade，the history of the maritime Silk Road and the formation of knowledge system about the Indian Ocean in the ancient Greek-Roman.