Landmine exclusion has always been a difficult problem. The detection of landmines by an infrared system mainly depends on the infrared radiation difference between the landmine and the background. Firstly, the main factors affecting ground surface temperature are analyzed according to the heat balance equation. Taking the one-dimensional heat conduction equation as a model, the influence of buried landmines on ground surface temperature is analyzed. The variation of the surface temperature of the soil above a landmine and its surrounding soil with time in a day is calculated and compared with the actual measured values. On this basis, fitting analysis is carried out on the experimental data by using the Gaussian model. With a fitting model, the variation relationship between the ground surface temperature and the time can be obtained. The results show that the simulated landmine can block the normal thermal conduction between the soil above it and its surrounding soil and hence result in the temperature difference between the soil above it and its surrounding soil. This temperature difference can be detected by infrared technology.