Qu Wan-Li (courtesy name Yi-Peng, 1907-1979) is one of the most influential scholars of contemporary Confucian classics studies. He mainly researches into Confucian classics, historical records, paleography, and textual bibliography, which marks an extraordinary achievement and thus makes him an iconic figure among coeval scholars. The materials of the New Text Book of Documents Qu studies can be divided into two, the "the original sources" and "later generations' interpretations." He is especially great in verifying the completion years of the latter part. This paper proceeds in three sections: (1) clarifying that "verification of the completion year" and "authentication" are two different strands of Qu's thought and then elaborating on his achievement in the former; (2) identifying Qu's point of departure for the verification of the completion years of ancient writings and then generalizing the six methods he employs for it; and (3) discussing how Qu succeeds to Wang Guo- Wei and Fu Si-Nian's methodology and revises the trend of "doubting the ancient thoughts" from the perspective of "later generations' interpretations