Abstract: Hydrogenated diamond like carbon (α-C∶H) thin films were deposited on YG6 cemented carbide by linear ion source (LIS).The effects of substrate temperature on the microstructure,morphology,wear resistance and adhesion between film and substrate of the α-C∶H thin film were investigated using atomic force microscopy (AFM),Raman spectroscopy,ball milling and Rockwell hardness testing.Results show that the sp3 bond content and wear resistance of the α-C∶H thin film decreased first and then increased when substrate temperature rose,which was contrary to the surface roughness.The film prepared at substrate temperature of 80 ℃ had the lowest surface roughness and sp3 bond content,its wear resistance was the worst.The substrate temperature had no evident effect on the adhesion between film and substrate.