This paper is devoted to a study of an important monument of late Tangut Buddhism: The Repentance Ritual on the Platform of Ocean-like Samadhi from the Avatamsaka Sutra (大方廣佛華嚴經海印道場十重行願常徧禮懺儀). This text in forty-two chapters was composed by Yixing Huijue (一行慧覺), a monk of Tangut descent who was active in Yuan China at the beginning of the fourteenth century. This Paper summarizes current research on Huijue's life, his scholarly affiliation and other various aspects of his work, as well as the origins of the commentary attached to the text. The conclusion is that the commentary was not fully composed by the Yunnan Buddhist master, Cangshan Purui(蒼山普瑞) of the Yuan dynasty, but was partially authored by Huijui himself. Huijue mainly followed the late Tang and Liao tradition of Huayan thought and maintained the ideal of "perfect teaching" as formulated by Liao Buddhist masters, whose works had been available in Xixia either in Chinese or in Tangut translations. This puts Huijue into the mainstream of pre-Yuan Buddhist thought in northern China. He demonstrated substantial familiarity with the teachings of Tibetan Esoteric Buddhism. His Buddhism might be considered to be late Tangut Buddhism, a Sino-Tibetan amalgamation which later became instrumental in this present scholarly paper is more than a demonstration of the vitality of Tangut Buddhism during the early Yuan dynasty. This paper compares the work f Huijue with several other ritual texts which originated in Khara-Khoto and were discovered elsewhere. Among these ritual texts, special attention is given to The Ritual of Integrated Repentance (Yuantong Chanyi 圓融懺儀) from Khara-Khoto, The Huayan Repentances and recitations (Lichan niansong 禮懺念誦) recently discovered in China. The conclusion is that these texts belong to the same tradition which was based on the practice of the vows of Samantabhadra, which was popular during the Tang dynasty, but was later transmitted to Liao and Xixia.