Abstract: Existing studies on the deterioration of gypsum rock generally consider single influencing factors, whereas actual engineering environments often involve coupled hydro-thermal processes. To better simulate field conditions, this study investigated the mechanical and damage evolution characteristics of gypsum rock under freeze-thaw-water immersion coupling for the groundwater development and seasonal freeze-thaw conditions affecting the Huangyan Tunnel. Through the freeze-thaw cycle test and uniaxial compression test, the change characteristics of solution conductivity and specimen water absorption were analyzed. Then, combined with the mechanical and microscopic characteristics of the specimens, the evolution characteristics of gypsum rock freeze-thaw damage variables and tunnel damage depth ratio were revealed. It was found that with the increase in the number of freeze-thaw cycles, the conductivity of the aqueous solution, the degree of internal crystal fragmentation, and pore volume of the gypsum rock specimens gradually increase, while the brittleness gradually decreases. The uniaxial compressive strength, modulus of elasticity, and brittleness coefficient all decrease exponentially. Specifically, the peak stress decreases by 42.43%, whereas peak strain and Poisson's ratio increase by 114.06% and 106.25%, respectively. Failure is predominantly governed by tensile damage. The damage depth ratio between the freeze-thaw damage variables of gypsum rock samples and the damage depth of gypsum surrounding rock tunnels gradually increases and converges to 1. The study provides a theoretical basis for revealing the mechanical and damage evolution characteristics of gypsum rock under the coupling effect of freezing-thawing and water immersion, and it offers valuable guidance for the durability assessment and engineering design of tunnels in seasonal freezing regions.