Tungsten nanoparticles have been synthesized by the sonoelectrochemical method. The electrolyte contained the tri-sodium citrate, sodium tungstate, ferrous sulphate, and citric acid. A platinum slice was used as the anode and a titanium-alloy horn as the cathode. Twenty kilohertz ultrasound generated by an ultrasound generator was connected to the titanium-alloy horn as an amplitude converter. Due to the electrochemical reaction and the cavitation effect of the ultrasound, the iron-tungsten aggregates at the cathode were dispersed into the electrolyte and iron atoms were dissolved in the acidic environment. In this way, body-center-cubic (bcc) tungsten nanoparticles have been obtained by controlling the density of the electric current, the ultrasound pulse period and amplitude. Their morphology, structure, and chemical components have been characterized using transmission electron microscope (TEM) and X-ray photoelectron spectrometer (XPS).