To improve the tribological properties of traditional MoS2 films,Si/MoS2 composite film and two kinds of C-Si/MoS2 composite films were deposited on silicon wafers and 304 stainless steel by medium frequency DC magnetron sputtering.The composition and thickness of the films were characterized by scanning electron microscopy (SEM) equipped with EDS equipment.The friction and wear properties of Si/MoS2 and C-Si/MoS2 composite films under different humidity conditions were tested by vacuum friction and wear tester (CSM).The results show that the C-Si/MoS2 films with different carbon content have similar Si contents,and Si exists in the form of elements in the film.The friction coefficient of Si/MoS2 films is increased continuously with the increase of humidity.Compared with Si/MoS2 film,the friction performance of C-Si/MoS2 film doped with 49.08% (atomic fraction) carbon is optimized,and the friction coefficient is higher than that of pure Si/MoS2 film only at 24% humidity.The wear degree of C-Si/MoS2 thin film containing 49.08% carbon is the least,because C is easy to shear and slip in the friction process,by coupling lubrication with MoS2,which optimizes the tribological properties of the film.In vacuum,the wear mechanism of Si/MoS2 film and C-Si/MoS2 film is adhesive wear.However,in different humidity,oxidation wear and abrasive wear of Si/MoS2 film and C-Si/MoS2 film will occur because of water vapor and oxygen.