Abstract: Grain temperature is an important ecological factor of granary, and is the primary factor affecting grain quality. In order to reveal the regularity of temperature change in underground granary, the changing cloud chart of the temperature field in different months in one year of the underground granary was obtained by using theoretical analysis, numerical simulation and experimental research based on the boundary conditions of the heat transfer parameters of the silo enclosure structure and the grain storage environment according to the principle of thermodynamics. The results showed that the temperature was basically stable at less than 20 ℃, and there was an obvious temperature stratification in the granary over time. The upper temperature was higher than the bottom temperature under the influence of the outside temperature, and the bottom layer tended to be stable at low temperature. By comparing with the test results, the results of the numerical analysis were in agreement with the test results. The numerical simulation method could be used to predict the temperature of the underground storage effectively, and provide a reference for the study of other structure temperature fields.