Abstract:The Three Ancillary Palaces and the Three Ancillary Abodes of the Forbidden City are located on Outside West Road of the Forbidden City. The three ancillary palaces in the east-west direction and the three ancillary abodes in the north-south direction form an L-shaped architectural area as a whole. Based on the surveying and mapping data, relic researching and literature review conducted by the Engineering Management Office for the protection and repair of the Three Ancillary Palaces and the Three Ancillary Abodes of the Forbidden City, have sorted out the architectural layout and functions since it started built. During the Yongle of the Ming Dynasty, there were attached to the Renshou Palace; during the Jiajing of the Ming Dynasty, the Cining Palace was built. They were attached to the Cining Palace. In the early Qing Dynasty, its architectural layout and functions followed the old system of the Ming Dynasty; at the turn of Yongzheng and Qianlong, the Shoukang Palace was built, the architectural layout and shape of this area were reconstructed. Until the end of the Qing Dynasty, the area was used as annexes of the Shoukang Palace and served as the residence of the concubines. From the Republic of China to 2018, before the Project Management Office began to protect and repair the area, the architectural layout of the area has not been greatly changed. During this period, the Three Ancillary Palaces and the Three Ancillary Abodes were used as the Antiquities Museum and the Cultural Relics Restoration Factory of the Palace Museum.