Objective To fabricate Si-doped TiSiN nanocomposite coatings in SiH4 ambient, and to provide approaches to fabricate TiSiN nanocomposite coatings using SiH4 in industrial production process. Methods TiSiN coatings were deposited on Si and cemented carbide substrates by cathodic arc ion plating in SiH4 ambient. The effects of SiH4 flow rate on the chemical composition, microstructure, mechanical and tribological properties of the TiSiN nanocomposite coatings were systemically investigated. Results The SiH4 flow rate had an obvious effect on the chemical composition, microstructure, mechanical and tribological properties of the TiSiN nanocomposite coating. With the increase of SiH4 flow rate, the structure of fabricated TiSiN coatings changed from columnar grain to composite structure of nanocrystalline embedded in amorphous phase matrix. The Si added in the coatings was in the amorphous Si3 N4 phase, with the Si content increased, the grain size of TiN decreased, which had a grain refining effect. The microhardness reached up to 4100HV0. 025 at the SiH4 flow rate of 42 mL / min (6. 3 at. % Si in the coating). Friction coefficients of TiSiN nanocomposite coatings increased with the increasing SiH4 flow rate when tested against carbide balls, and the friction coefficient was less than 0. 6. Conclusion The TiSiN nanocomposite coating of nanocrystalline embedded in amorphous matrix could be fabricated in SiH4 ambient. The microhardness was relatively high. SiH4 could be used for the deposition of TiSiN nanocomposite coatings in commercial process.