To study the effects of technical parameters, such as geocell specifications and laying types, on the bearing capacity and deformation of highway subgrades in oasis flood irrigation areas, the shear properties of plain soil and geocell-reinforced layers with different specifications were studied through large-scale direct shear tests. Based on indoor compression tests and field load tests, numerical simulation parameters, such as the deformation modulus of different foundation soil layers, were calibrated. A numerical model of the geocell-reinforced highway subgrade was established using , and the effects of geocell specifications and laying types on the vertical settlement of the subgrade, the displacement of the slope toe, and the vertical stress under the reinforced layer were systematically analyzed. The results show that geocells with different specifications can effectively reduce foundation settlement. The reinforcement effect of the geocell with a welding spacing of 40 cm is superior to that of the geocell with a welding spacing of 80 cm, and the reinforcement effect is enhanced with the increase in the number of geocell layers. Before and after the geocell treatment, the variation trend of the horizontal displacement of the slope toe along the depth direction is consistent. The maximum values of both appear at a depth of about 2 m, then gradually decay, and tend to be identical at 6 m, with the influence depth of the geocell reaching 4?5 m. After the subgrade is reinforced by geocells with different specifications, due to the influence of boundary conditions, the geocells undergo flexural deformation after being stressed, exhibiting characteristics similar to the settlement of the foundation surface. At the same time, due to the substantial anti-deformation performance of the geocell-reinforced layer, a stress diffusion effect is generated, which reduces the vertical stress inside the foundation. According to the results of the large-scale direct shear tests, the indoor compression tests, and the numerical calculations, replacing the soil with a mixture of geocells and gravelly soil can effectively improve the strength and modulus parameters of the replacement materials and reduce the subgrade deformation. On the one hand, the construction volume of highway construction units is reduced, which greatly reduces the carbon emissions caused by construction; on the other hand, the harm caused by the construction of high-grade highways to the ecological environment along the oasis-desert areas is reduced, and land resources are saved. The research results can provide a certain reference for the application and theoretical research of geocells in highway engineering in oasis areas.