The plate impact experiments have been conducted to investigate the dynamic behavior of 91W-6.3Ni-2.7Fe with three kinds grain sizes of 1− 3μm, 10 −15μmand 30 − 40μm . The stress-time history curves at different Lagrangian positions were obtained for tungsten alloys at different impact velocities. Lagrangian analysis technique was adopted to discuss the mechanical properties of the tungsten alloys under high strain rate. SEM was introduced to analyze the microstructure properties of tungsten alloys. The influence of grain size on the dynamic behavior of tungsten alloys under high strain rate was obtained and the stress-strain curves ( 4 5 1 10 ~ 10 s− ) of the tungsten alloys were given.