Apreparation method of ultra-high molecular weight polyethylene (UHMWPE) fiber bundle samples was designed to effectively prevent fiber pull out and root shear fracture of samples. Based on the experimental data of axial tensile test, the temperature and strain rate effects of mechanical properties of UHMWPE fiber bundles and their failure modes were investigated under 25 kinds of working conditions including temperature (－60~80 ℃) and strain rate (1×10-5~3.3×10-2 s-1). The results show that the mechanical properties of UHMWPE fiber bundles have certain strain rate and temperature effects, but the latter has a more powerful influence, which makes the strength of UHMWPE fiber bundles decrease significantly when the temperature is higher than 50 ℃. In addition, low temperature can improve the tensile strength of UHMWPE fiber bundles and weaken the strain rate effect of mechanical properties. In the range of －40 ℃ to －60 ℃, the tensile strength and failure strain of UHMWPE fiber bundles are not affected by strain rate. In the investigation of damage and destruction modes of UHMWPE fiber bundles, it is found that the critical strain rate of brittle- tough transition is closely related to temperature in the temperature range of 25~80 ℃, and the critical strain rate will increase by an order of magnitude every time the temperature increases by about 30 ℃.