First of all, the origin of the DLC film friction performance was analyzed from the point of bonding structure, and then the main factors of friction properties of diamond films and the influencing law were discussed from the three aspects: deposition process of DLC films (including the preparation method, the type of the gas source and doping elements), friction environmental conditions and substrate materials. It was concluded that: the content of sp2 in the carbon and the hydrogen content in the DLC film could be changed by adjusting the deposition process of DLC films, and then the tribological properties of the DLC films were influenced; vacuum, inert gas and low humidity environment were beneficial to better friction performance; the transition layer and the bias could improve the adhesion between the DLC film and the substrate, and enhance the friction performance. At last, the paper reviewed the applications of DLC films in mechanical processing and wear resistance, optical and electronic protection, analyzed the two major problems in the application process, namely, the internal stress and thermal stability of DLC film, and summarized the corresponding solutions. The development trend of DLC films was prospected as well.