The use of natural fibers as composite reinforcement has various advantages, including as substitute for artificial fiber, low price, able to reduce sound, environmentally friendly, has low density, good fit and ability to absorb impact energy, making it possible to use it as a vehicle accessory such as a rear bumper vehicle. This study aims to investigate the impact toughness performance of the fiberglass matrix composite polyester (FMCP) reinforced fiber Musa acuminata stem fiber (MASF), with a volume fraction of 5%, 10%, 15%, 20% and 25%. Polyester matrix type 157 is used BQTN and G3253T, MEKPO catalyst. The impact toughness test was carried out by using the charpy method impact test instrument, observing the microstructure of the occurrence of fracture by using scanning electron microscope (SEM). The composite impact test specimen was 12.7 thick mm refers to the ASTM D 256 standard, produced by the hand layup method. The most optimal volume fraction impact test at a volume fraction of 20% MASF: 80% Matrix, with an impact energy of 14.47 J, impact toughness 0.094 J/mm2. The results showed that the addition of MASF increased the impact toughness of the composite by 14.69% compared to composites 0.0122 J/mm2. Based on SEM observations, it can be seen that the 20% MASF volume fraction of the bonds between the matrix and the fibers are perfectly integrated. The results showed that the addition of MASF increased the impact toughness of the composite by 14.69% compared to composites 0.0122 J/mm2. However, if a volume fraction ratio above 20% MASF is used, the impact toughness is decreased.