Abstract: The large-scale exploitation of methane hydrate-bearing clay through carbon dioxide displacement holds significant importance in reducing carbon emissions and maintaining strata stability. The clay sediment containing CO₂ hydrates during the replacement process is called carbon dioxide hydrate-bearing clay. By analyzing the experimental data available in literatures, the phase equilibrium curve of methane-carbon dioxide hydrate is obtained. The relationships among the condition parameter L, strength and elastic modulus of carbon dioxide hydrates are established. These relationships can be incorporated into the microscopic contact model for grain-cementing type methane hydrate-bearing clay in the discrete element method (DEM) to finally build a three-dimensional contact model of grain-cementing type for the structured carbon-dioxide hydrate-bearing clay. The model can consider the effects of different carbon dioxide mole fractions. Based on the built contact model, a series of isotropic compression tests and conventional triaxial compression tests are conducted through the DEM simulation, and the simulated results are compared with the present laboratory experimental ones. The results show that the proposed contact model in this study can characterize the change laws of mechanical properties of the structured carbon dioxide hydrate-bearing clay, which can provide technical reference for the exploitation and utilization of methane hydrate in the future.