In this paper, by establishing and validating a three-dimensional model of heat transfer in multi-layer heat preservation boxes during non-refrigerated food transportation, the key role of radiation heat transfer in packaging boxes is revealed besides conduction. By reducing radiation, the amount of aluminum foil added on the inner surface of food during the first 30 hours of storage was reduced by more than 10%. Putting the initially frozen gel pack in the center of the box can obviously delay its melting and double the storage time of the food. The sensitivity analysis shows that the conductivity of box wall, the emissivity inside the box surface and the emissivity of the gel bag are the key parameters affecting the performance, while the influence of the convection heat transfer coefficient is not very significant.