Abstract: The influence of carbon content on the shape and the magnitude of intermetallic phase in higher tungsten content heavy alloys has been studied.The measurement of dynamic mechanical properties of these alloys was performed on Hopkinson Bar appartus.The results showed that there was only a small amount of intermetallic phase formed along tungsten grain in 99W without carbon.with the carbon content increased,the magnitude of intermetallic phase increased and the shape of the intermetallic phase changed gradually from shell to needle plus grains,then flake.This increase ment of the intermetallic phase can make the tensile strength descend obviously,but the compressive strength changed little.