Abstract: Ultrafine tungsten powder is an important raw material for producing cemented carbide. At present, the main method of preparing it is hydrogen reduction of tungsten oxide in industry. How to mass-produce uniform one at low cost has always been a hot area of research. In this paper, a controlled variable method was used to carry out blue tungsten hydrogen reduction experiments to explore the influence of reduction temperature, hydrogen flow rate and reduction time on the microstructure of prepared tungsten powder. A large number of needle-shaped crystals which might be violet tungsten appeared, when the reduction temperature, hydrogen flow rate and reduction time was 700 ℃, 150 mL/min, 55 min, respectively.