《The Avatamsaka Sutra》, also named in English as《The Flower Garland Sutra》, is one of the most influential Mahayana sutras of East Asian Buddhism. It has three complete Chinese versions. The first complete Chinese version was completed by Buddhabhadra around A.D. 420 with a scale of 34 chapters in 60 scrolls. The second was by Śikṣānanda around A.D. 699 with 40 chapters in 80 scrolls. The third one was only for the Gaṇḍavyūha section, which was completed by Prajñā around A.D. 798 . This thesis targets at a study of Dunhuang manuscripts about the《The Avatamsaka Sutra》translated by Buddhabhadra in the Jin Dynasty. We study a total of 217 pieces of Dunhuang documents, including 197 pieces of Buddhabhadra's, 18 pieces of Śikṣānanda’s, and 2 pieces of Prajñā’s. This thesis is divided into five chapters with a structure as follows: (1) the first chapter, "Introduction" provides a general explanation and an overture to this treatise; (2) the second chapter focuses on describing the history of 《The Avatamsaka Sutra》, including its’ becoming, Chinese translation, and spreading; (3) the third chapter analyzes the difference between 《The Avatamsaka Sutra》50 scrolls and 60 scrolls in the Chinese Buddhist canon; (4) the fourth chapter deals with 197 pieces of Dunhuang manuscripts about《The Avatamsaka Sutra》by Buddhabhadra, including the completion of describing manuscripts, patching-up of fragments and identifying manuscripts; (5) the fifth chapter is a concluding report of the research results. Our conclusions on this studies are as follows: (1) 62 pieces of Dunhuang manuscripts were retained in the inscription with volume number, which makes ascertaining of the 50 scrolls in《The Avatamsaka Sutra》; (2) it is now available to draw the original appearance of Dunhuang《The Avatamsaka Sutra》50 rouleau manuscripts; (3) Patching-up 69 fragments into 29 groups makes the defragment of Dunhuang manuscripts of《The Avatamsaka Sutra》; (4) Dunhuang manuscripts of《The Avatamsaka Sutra》has contributed a value of textual criticism to Chinese Buddhist canon.