In his old age, he confirmed the confines and tasks of philology, summarized the experiences and achievements of criticizing texts in history, put forwarded the important works of textual criticism.

• 在晚年建构历史文献学学科体系时,他确定文献学的范围和任务,总结前人整理文献的经验和业绩,提出今后整理文献的重要工作,具有前瞻性。