Abstract: Aimed at the environmental and mechanical characteristics of shield-driven tunnels, this paper establishes a 1D unilateral erosion test method for segments under the combined influence of chloride erosion and structural load and presents the results of tests conducted using a test device that was developed in a simulated environment. Furthermore, it discusses the influence of chloride ion concentration, erosion time, and load level on chloride ion diffusion and content distribution. The results show that the chloride ion content in the concrete cover increases gradually with the increase of chloride ion concentration and erosion time; the pore characteristics inside the concrete are changed by external loading, which directly affects the chloride ion penetration, manifesting in the fact that penetration is easier under tensile stress rather than compressive stress.