Abstract: In order to reveal the interaction between ground and the support in weak rock tunnels, the Shijiashan Tunnel, which is the key project for China's first tourism rail transit project, is investigated, and a test platform that can control ground deformation is developed. The ground deformation is used to represent the installation timing of support, and the geomechanical model test is conducted. The study results suggest: (1) The installation timing of support will significantly affect the dynamic evolution and distribution of radial compression and tangential stress of soft ground. (2) Under different controlled deformations, the radial stress release of ground always experiences three stages of development as deformation increases. (3) Under the same deformation, the radial stress response characteristics of different parts of the tunnel differ noticeably, and as controlled deformation increases, the response speed of different parts change obviously. (4) Increase of controlled deformation causes the ground failure response speed of different parts of tunnel to be faster, the core area of failure is shifted, and the non-uniformity of tangential stress distribution increases significantly. (5) The structural support is appreciably affected by the installation timing of support, and the radial stress release of shallow ground is controlled by the preliminary minor deformation. When deformation reaches a certain threshold, stress release becomes unobvious, while the disturbance depth expands, the stress of deep ground is released, and the disturbance zone and failure zone of ground expand faster.