AbstractBagasse is a renewable resource characterized by its low cost and environmental friendliness. In this work a novel technological process was proposed to make flame retarding composites (BFRCs) by using bagasse fiber. The bagasse was disintegrated by twisting it up and applying high consistency refining, and then it was used to prepare BFRCs via hot pressure. Chemical groups and thermal properties of bagasse fiber were studied through the use of FTIR spectroscopy, a universal mechanical testing machine, and TGA, while properties of BFRCs were also analyzed by SEM, and the surface water resistance and burning characteristics were measured. Results showed the pyrolysis temperature of bagasse fibers to be about 273oC. Chemical groups were not changed, while the content of groups was reduced a little during the manufacturing process. The BFRCs showed good performance for water resistance, and the optimum value was 1.7 g. They also had good flame retardant performance. The index of flame spread was 13.6 and the smoke index was 108, which reaches Class A by the ASTM E84-08 Standard.