Abstract: In this study, hollow glass beads (HGB) were introduced into an aromatic thermosetting polyester (ATPE) based foam to prepare HGB/ATPE composite foam, and effect of content of HGB and foaming conditions on the properties of HGB/ATPE composite foam were investigated. After modification, the specific strength of the HGB/ATPE composite foam can reach 26.2 MPa/(g·cm⁻³), respectively. Moreover, the addition of HGB also greatly improves thermal properties and flame resistance performance of the HGB/ATPE composite foam. The thermal decomposition temperature, glass transition temperature and heat distortion temperature of the HGB/ATPE composite foam are 494.18℃, 230.47℃ and 191.00℃, respectively, and the limiting oxygen index can reach 35%–37%.