The temperature field in a nuclear waste repository is an important issue with regard to the design and safety assessment of the repository. In this paper, a double-layer model for simulating the heat conduction near a single waste canister is established, and then, by applying the Laplace transform to the governing equations of the heat conduction in the buffer layer and the surrounding rock, the solutions of the temperature field are obtained in the Laplace domain. The temperature distribution near the nuclear waste canister is presented by numerical inversion of the solutions using Crump’s method in the time-space domain. Finally, the effects of parameters on the temperature on the canister surface are analyzed. The results show that the double-layer model of the heat conduction increases the maximum temperature on the canister surface by about 11.87°C compared to the single-layer model. The double-layer model is verified to be reliable by comparing with a line heat source model that has been verified by numerical calculations. The temperature on the canister surface is significantly affected by the burnup value and cooling time of the nuclear waste, the thickness of the buffer layer, the thermal conductivities of the buffer material and the surrounding rock, and the external boundary condition.