Due to the influence of geological structure and stress concentration, the peripheral rock is prone to deformation and rupture in large cross-section tunnels under high geo-stress environment, which leads to lining instability, increased construction difficulty and safety hazards. In order to explore the influence of high geo-stress on tunnel construction, the response of tunnel surrounding rock and the internal force characteristics of the initial support structure under different construction methods and geo-stress conditions were investigated through model tests. The test results show as follows. Under high stress conditions, the surrounding rock shows inward extrusion, and the stress evolution is divided into two stages: disturbance and stability, and the stress tends to be stable when the excavation surface is about 1.5 times the diameter of the tunnel from the monitoring section. The comparison of the three methods of construction reveals that the maximum axial force and bending moment of the initial support are concentrated in the top of the arch and the centre of the superelevation arch, so it is recommended to strengthen the support and the pre-strengthening measures, and to complete the initial support closing and second lining construction in a timely manner. The model test reveals four stages of initial support damage: Microcracks sprouting in the arch and the back arch → cracks expanding to the foot of the arch → cracking and misalignment in the back arch → overall deformation and instability of the lining. The study shows that it is necessary to focus on strengthening the support measures for the vault, the back arch and the foot of the arch to ensure the safety and stability of the tunnel structure.