The W coatings prepared on structure materials (V-4Cr-4Ti) as plasma facing materials, not only can release impinging thermal power but also can resist erosion under plasma particles bombardment in international thermonuclear experimental reactor. The electro deposition of W in Na₂WO₄-WO₃ melt as a promising technique was studied in this work. The effects of current density on microstructure and mechanical properties of W coating were investigated, and the results show that, with the increasing of the current density, the trend of crystal growth is promoted and the grain size of W coatings increased. The nucleation easily occurs on V-4Cr-4Ti alloy substrate for W atom, and after that, the growth of crystal nuclei is the most important factor for the formation of coatings. When the current density increases to 100 mA/cm², the metallographic structure of W coatings presents columnar or stripy structure, and tooth-like grains were presented in microstructure as current density is lower. The Vickers micro-hardness of W coatings is decreased as increasing current density, and the adhesive strength of the coatings is greater than 59.36 MPa by the tensile test. Although the thickness of tungsten coatings is 10 μm as current density is 10 mA/cm², grain size is less than 5 μm, Vickers hardness, current efficiency and the coatings adhesion are all maximum, and the values are 628.42 HV, 99.71% and 96 N respectively.