1925 After graduation, I worked as a teaching assistant in Tsinghua University National Studies Institute. Under the guidance of Wang Guowei, he laid a solid foundation in literature and history, drama, epigraphy, edition, bibliography, collation and other disciplines. From 65438 to 0928, he was transferred to Beiping Beihai Library (from 65438 to 0929, he was merged into the National Beiping Library and is now the National Library of China). He has been the leader of the Chinese interview team, the review team of rare books, the editor, the editor-in-chief of National Beiping library journal, the director of the headquarters of rare books, the distinguished researcher of the Institute of History and Language of Academia Sinica, and the distinguished member of the Library and Documentation Museum of the Palace Museum. He also taught in Peking University, Tsinghua University, China-France University, Fu Jen Catholic University and China University, and taught China Bibliography, Bibliography, Collation, Edition, China Woodcut History, China Opera History, China Popular Literature History, Ci History and other courses. 1949, he served as researcher of Beijing Library (now the National Library of China) and director of the special collection department of ancient books. 1964 was elected as a deputy to the Third National People's Congress. 1979 was elected honorary director of library society of china.