Artificial mountains have rich levels of landscape hierarchy and are an important component of Chinese classical garden art. In modern garden design, they mainly play a role in increasing the local landscape effect. Due to the large volume of artificial mountain construction, it will carry a significant load and experience significant settlement deformation during long-term application. Once the deformation is too large, it can cause the mountain to crack. Therefore, a settlement monitoring method for plant garden rockeries based on 3D laser scanning technology is proposed. Determine the scanning density through the principle of 3D laser scanning, and obtain the 3D coordinates of the point cloud data of plant and garden rockeries according to standard parameters and scanning density; Using the collinear condition equation to decompose the three-dimensional coordinates of the point cloud, determine the relationship between the three-dimensional coordinates of the point cloud data and the spatial coordinates of the object, and obtain the inner and outer orientation elements in the point cloud coordinates; By using the spatial rendezvous calibration method and considering optical distortion, the orientation elements are calibrated to construct a coordinate difference equation for the main point of the image, obtain the settlement deformation of the plant garden rockery, and complete the monitoring method design. Taking a forest garden in a certain city as the test object, the research method was used to monitor the settlement of artificial rockeries in the garden. After data comparison, it was found that the research method has precise monitoring effects and can effectively complete the monitoring of rockery settlement deformation.