The Lion Forest Garden was originally built in 1342, during Yuan Dynasty, and became one of the most famous gardens in Suzhou. In 2000, it was inscribed in the World Heritage List as an extensive property of the Classical Gardens of Suzhou. The Lion Forest Garden is famous for its stony artificial hills covering more than 4,000 square meters, which were continually built during Yuan, Ming, and Qing Dynasty. However, as a long time passed, stony artificial hills appear damaged showing stone cracking - which could be seen in many places-, gaping, weathering, water erosion, and subsidence. Besides, a new underground line will pass through the road west to the Garden. In 2018 and 2019, the Landscape Architecture Engineering Lab of the Beijing University of Civil Engineering and Architecture collaborated with the Lion Forest Garden Administration on a research to define the strategy to monitor these stony artificial hills. Multiple technologies were used, such as 3D Scanning, Ultrasonic Testing, Side-Scan Sonar, sensors, and so forth. During the monitoring, some technologies worked well while others did not. The paper, based on the mentioned research, will discuss the strategy and technologies used in monitoring historical rockeries, describe the procedure, analyse the outcomes, and find out the reasons causing the unsuccess of some technologies.