This paper analyzes the development process of the mansion in Henan area, studies the Baiju Yilufang mansion in the Tang Dynasty, and tries to draw its plan, façade and bird’s-eye imaginary map according to historical records. The investigation visited three existing mansions (Liu Residence in Liujia Hutong in Kaifeng, Renjia Mansion in Yucheng County and the Former Residence of Wang Duo in Mengjin), and drew a plan and bird’s-eye view of the Quasishan Garden (the back garden of Wang Duo’s mansion) according to written records. Through the analysis of historical background and existing examples, and the comparison of Jiangnan private gardens, it is pointed out that although Henan’s ancient mansions are private gardens, their style is more inclined to the type of palace garden. In the composition, there is an axis treatment of shaping, and attention is paid to the use of mountains, stones, and water trees to find natural changes.