Abstract: Silane coupling agent was used to pre-treate hollow glass bead, and then to prepare a polypropylene(PP) foamed composite modified by hollow glass bead (HGB) by post-foaming process in designed dies. The effects of the mass fraction of HGB on foaming effect, interfacial bonding and mechanical properties of the foamed composites were studied. The results show that adding HGB modified foaming effction dramaticlly. When the mass fraction of HGB was 15wt%, a close-cell structure with uniform cell distribution and fine cell size was obtained, and the mechanical properties of the foamed composite was best, and its impact toughness, flexural strength and compressive strength was 25.6 kJ·m-2, 11.2 MPa和17.6 MPa, respectively. The surface pre-treatment by KH550 enhanced interfacial bonding between HGB and PP matrix and strength of cell wall signally.