Abstract: The thermal conductivity of compacted bentonite is very crucial in evaluating the safety of heat dissipation and in calculating the temperature distribution of radioactive waste repository. An accurate predictive model is of great significance to the calculation of their thermal conductivity under various conditions. A mesoscale model is proposed for the thermal conductivity of compacted dual-porosity bentonite by numerical simulation. The thermal conductivity of 160 measured samples is selected and compared with their simulated one for five typical kinds of compacted bentonite with different dry densities and water contents. The results show that the most predictive values are within ±20% range of the measured ones, which verifies the reliability of the model effectively. The results in this study provide a new approach and/or strategy to predict the thermal conductivity of the compacted dual-porosity bentonite.