Based on Brinkman-extended Darcy model, using pressure and velocity coupling SIMPLE under algorithm rectangular coordinate system, heat transfer characteristics of loose granular material under the vertical diraction heat source were simulated. The results showed that the granular material under the vertical line heat source had obvious convective heat exchange effect, and no obvious correlation with grain size and porosity. The average heat source surface Nusselt number, Nuavg, linearly increased with increasing of Ra, and the relationship between local heat source surface Nusselt number, NuR, and Ra was relatively complicated, but except the top of the heat source surface, the measuring positions could be described by NuR=aRa2+bRa+c. Thus, in order to reduce the effect of convective heat exchange, when the data of heat surface temperature were used to evaluate the thermal conductivity coefficient of sample (cross line method), the experimental time should not be more than 120 s. When the thermal physical parameters of sample were measured by parallel line method, the appropriate temperature measuring points should be located at its tube part positions (Y<0.33). the model prediction of temperature rise at typical measuring points was coincident with the measured results. But there was the maximum temperature deviation of 17℃ between the prediction of heat conduction model and measured results. The measuring point temperatures in the middle and low area had smaller deviation.