Under the humidification condition, the strength parameters of the expansive soil will decrease and the expansion force will be generated. Under the combined action of the two, the stability of the surrounding rock of the expansive soil tunnel will be seriously reduced. Therefore, it is necessary to study the deformation and lining stress of the surrounding rock of expansive soil tunnel under the condition of humidification. In this paper, laboratory tests and numerical simulations are used to study the stability of the surrounding rock of the expansive soil tunnel. First, the shear experiment is carried out on the remolded expansive soil with different water contents, and the fitting relationship between friction angle and cohesion and water content is obtained. Then, the ABAQUS finite element software is used to simulate and analyze the excavation process of tunneling in the expansive soil.The temperature field module is used to simulate the humidification and expansion of the surrounding rock of the tunnel, and the stress and displacement of the tunnel before and after swelling were obtained. At the same time, the orthogonal experiment was designed to analyze the influence of various factors on the stability of the shallow buried tunnel in the expansive soil. Results show that after humidification, the stress value at the arch waist of the surrounding rock increases significantly, the stress value at the vault and arch bottom decreases.The longitudinal displacement value at the lining arch bottom increases, and the longitudinal displacement value at the arch top decreases. By designing orthogonal experiments and using range and variance analysis, the most influential factor on stability of the surrounding rock of the expansive soil shallow tunnel is the humidification strength, followed by the over-span ratio, the swelling thickness and the swelling coefficient.