Zhang Yu was a noted proofreader toward the end of Qing and at the beginning of the Republic period while Li Wentian was a noted historical figure toward the Qing Dynasty. Both were famous collectors, with a high attainment especially in the collection of ancient books and rubbings. The Sidangzhai of Zhang Yu is noted for manuscripts and proofread copies while the Taihualou of Li Wentian is noted for the collection of rare editions. In the 1930s, their collections were transferred, due to different reasons, to the Yanjing University library. Their affinity changed again later on. Hardly anyone at present knows about this. The article introduces this part of the history and the information about the collections of Sidangzhai and Taihualou, which can be used as reference materials for studying the two collectors and the origin of the collection of the Yanjing University library. Zhang Yu was a noted proofreader toward the end of Qing and at the beginning of the Republic period while Li Wentian was noted for historical figure toward the Qing Dynasty. Both were famous collectors, with a high attainment especially in the collection of ancient books and rubbings The Sidangzhai of Zhang Yu is noted for manuscripts and proofread copies while the Taihualou of Li Wentian is noted for the collection of rare editions. In the 1930s, their collections were, due to different reasons, to the Yanjing University library. Their affinity changed again later on. Hardly anyone any present knows about this. The article introduces this part of the history and the information about the collections of Sidangzhai and Taihualou, which can be used as reference materials for studying the two collectors and the origin of the collection of the Yanjing University library.