Abstract: A series of tensile experiments with the testing strain rate ranging from 10^-4 to 10² S^-1,were performed for glass fibre,kevlar-49 and carbon fibre bundle-s by DT-5000 Material Testing Machine and a self-designed Pendulum Tensile Impact Set-up. It was the first time to obtain the stress-strain curves of above materials at high strain rates.The results show that for glassfibre the strength,fracturo strain and critical strain energy density are very sensitive to strain rate, and the elastic modulus increases with the rising of the rate.For the kevlar-49 fibre,the strain rate sensitivity is reduced:And for the carbon fibre,however.the mechanical properties are indepen dent of the strain rate.