Abstract： The heat transfer performance of square tube reinforced GFRP sandwich roof panel in hotsummer and coldwinter area was investigated. Based on the structural characteristics and the equivalent heat transfer theory of sandwich panel, the calculation formula of heat transfer coefficient was proposed for the sandwich panel. The thermal properties of four kinds of square tube reinforced sandwich panels of unfilled material, glass wool, extruded polystyrene board and polyurethane were investigated by steadystate heat transfer protection hot box test. The results show that the theoretical calculation results of heat transfer coefficient of the square tube reinforced sandwich panels are close to the experimental results and can be used for the calculation of heat transfer coefficient of similar structures in engineering. The heat transfer coefficients of the square tube reinforced GFRP sandwich panels filled with three kinds of filler materials of glass cotton, extruded polystyrene board and polyurethane foam board are respective 0.553, 0.471 and 0.377 W·m-2·K-1, and which can meet the requirements of design standard for energy efficiency of public buildings（GB 50189—2015）for thermal performance of roof panel in hotsummer and coldwinter area. The thermal bridge effect of square tube reinforced GFRP sandwich panels filled with polyurethane foam board is the least, which is more suitable for building roof panels.
