Abstract: The composition,structure and properties of Cu-W alloy thin films with W fraction of atonic number 2.1 %—53.1 % prepared by magnetron sputtering were characterized by EDX,XRD,TEM,SEM,microhardness instrument and four-point probe resistance meter.The effect of different W content on the structure and properties of Cu-W thin films was discussed in detail.The results show that Cu-W thin films possess nanocrystalline structure.Cu-W thin films with 2.1 %—16.2 %W fraction of atomic number possess fcc Cu(W) non-equilibrium metastable supersaturated solid solution,the film with 36.0 %W fraction of atomic number possess fcc Cu(W) and bcc W(Cu) two-phase solid solution,Cu-W thin films with 48.7 %—53.1 %W fraction of atomic number possess bcc W(Cu) metastable supersaturated solid solution.The microhardness of Cu-36 %W with two-phase is the highest(714MPa),the electrical conductivity of Cu-W films decrease with the increment of W contents.After annealed at 400 ℃ for 1h,the Cu-W films reveal a coarseness in the grain size of the matrix phases,the microhardness decreases,but the electrical conductivity increases.The evolution of structures and properties of Cu-W thin films after annealing are mainly attributed to the growth of matrix phase grain during annealing.