Damping and mechanical properties of bast fiber reinforced composites are important and key issues for their applications in manufacturing vehicle body components of automobile and high-speed train.Therefore，this work experimentally studied the kenaf fiber reinforced polypropylene composites. Investigation on the effect of fiber weight percentage on vibration characteristics and mechanical properties was carried out through mechanical tests and modal analysis.The results indicated that the tensile strain decreased with the increase in fiber content.The tensile modulus and tensile strength showed a rising trend with fiber content increase.Natural frequencies of the composites improved with fiber content increase in both the 1st and 2nd vibration modes.The damping ratio initially increased with the increase of fiber content before 10%，and then decreased after 10%. The highest composite damping ratio was of 0.093 obtained at 10% fiber content，which increased by 20.8% compared with the pure polypropylene.The damping ratio of the 2nd mode was higher than that of the 1st mode for each kenaf/pp composite.This suggests that damping properties of the kenaf/pp composites are related to vibration amplitude.