Yuan Ming Yuan, a large royal garden created and operated by the Qing Dynasty emperors for more than 150years, is located in Haidian District, a western suburb of Beijing and plays a very important role in world history. This paper uses Yan Qing Tang site as an example for exploring how to preserve other structures in the Yuan Ming Yuan ruin. The survey utilized four manuallydug exploratory wells to clarify part of Yan Qing Tang''s foundations, specifically to provide information about the natural and saturated uniaxial compressive strength of the limesoils using the uniaxial compression test. The uniaxial compressive strength of the limesoils at different depths was analyzed and compared. We conclude that the marble stone foundation is in danger of being lost and needs special protection; the top and the base of the concrete foundation have low uniaxial compressive strength while the middle part has higher strength. Both the stone foundations and the limesoils exposed at the surface need protection.