The quasi-static tensile properties and dynamic tensile properties of as-sintered 90W-7Ni-3Fe (90W) alloy were studied. Quasi-static tensile tests were carried out by a CMT4105 tensile machine at the strain rate of 0.001 s-1, while dynamic tensile tests were carried out by Split Hopkinson Tensile Bar (SHTB) within a higher strain rate range of 1600~2000 s-1. The tensile properties and failure mechanism of 90W alloy at different strain rates were investigated. Results show that under the condition of tensile loading, 90W alloy exhibits an obvious strain rate effect. With the increasing of strain rate, the tensile strength increases obviously, while the critical true strain for fracture and the total energy absorbed by 90W alloy show a decreasing tendency. The failure mechanism of 90W alloy converts from the abruption of W-W boundaries to the cleavage of tungsten grains.