Abstract: In order to investigate the heat transfer mechanism for isosceles-trapezoid honeycomb core of glass steel sandwich panel, experiment measurement using thermal conductivity meter and simulation investigation on heat transfer performance of sandwich panel were conducted. The results indicate that simulation results for the steady thermal conductivity coefficients of sandwich panels are identical with the calculation results of Swann and Pittman empirical formula, which validates the reasonability of cell plane model for numerical calculation. Part2 is the main steady heat transfer part for sandwich panel, so Part2 cell-wall thickness and side length have strong influences on thermal conductivity coefficient of sandwich panel, and the influences of Part2 height, Part1 and Part3 thickness as well as panel thickness on thermal conductivity coefficient is weak. Meanwhile, if only the thermal conductivity coefficient of sandwich panel is needed to be reduced and ignoring the demanding for static mechanical properties of sandwich panel, the honeycomb core layer material should be replaced; if both of the heat-insulation performance and static mechanical properties of sandwich panel are required to be satisfied at the same time, the multilayer honeycomb core of sandwich panel is an excellent choice.