Abstract: The Shuimocun garden and the Ziyiyuan garden were two famous gardens built by the Mingzhu Family in Haidian area in early Qing Dynasty. Due to scarce historical documents, the locations of the two gardens and their relationship were not clear, and arguments between scholars was sharp. In this paper, on the basis of research by Mr. Zhang Bao-zhang, Prof. Jia Jun, Prof. Cao Xun, Mr. Jiao Xiong and other scholars, in combination with more textual research and field investigation, we draw the following conclusions: ① The Shuimocun garden was a big garden built before 1685 A.D. by the Mingzhu family in the east of the Shuimocun village (north part of today's Tsinghua University) in early Qing Dynasty. ② The Ziyiyuan garden was a big garden built by the Mingzhu family in 1687 A.D. in the east of the Weng hill (today's Wanshou hill) after the Shuimocun garden had been built. It had been rebuilt to be prince Guo's Zideyuan garden in 3rd year of the reign of Yongzheng. The existing part of the Zide garden (south yard of today's Central Party School) occupies 2/3 area of the Ziyiyuan garden.