Thermal bridges are weakly insulated areas in the envelope of a building that can significantly increase the energy load due to heat dissipation. To improve energy efficiency, a thermal bridge model is established to simulate heat transfer through the column in a refrigeration room. The accuracy of the numerical simulation program is verified by experimental data. A heat preservation method for the column that minimizes the cooling loss is analyzed. The results show that the thermal bridging is mainly due to the steel bar in the column, because the share of the cooling loss attributed to the steel bars is 42.02-55.87%. Moreover, applying heat insulation on the column can provide more energy savings in low-temperature rooms than in high-temperature ones. The most economical thermal insulation method as a function of the height and thickness of the insulation layer is therefore proposed for the low-temperature column. By the optimum method, the amount of heat flux through the whole column section, which includes both reinforced and non-reinforced areas, decreases by 37.34%, and the total cooling loss decreases from 30.23 to 13.66 W, representing a 54.81% reduction. Therefore, a reduction in the cooling loss from thermal bridging is achieved for a low-temperature refrigeration room.