This essay discusses the chapter "Gaozong's Worship of the Sun" in the Book of Documents. It casts doubt on the findings of Wang Guowei, which were based on his analysis of oracle bones. Wang opposed the traditional theory that the piece was about Wu Ding's sacrificial ceremony for King Tang of the Shang dynasty, and asserted the views of Jin Lvxiang and others that the piece concerned Zu Geng's sacrificial ceremony offered to Wu Ding. However, the traditional theory holds true and is supported by the texts of bamboo slips "The Admonition from Bao Shuya and Xi Peng" preserved in the Shanghai Museum, as well as other bronze inscriptions of the Zhou dynasty. Even so, the original meaning of "Gaozong's Worship of the Sun" may not be known for certain until there are more materials and discussion. In any case, these bamboo slips help us understand some difficult lines in "Gaozong's Worship of the Sun".