In this paper, the deposition processes of CrAlN coatings on high speed steel (M2) substrate was mainly researched, which made by reactive direct current (DC) magnetron sputtering with AlCr alloy target. The effects of technological parameters (Ar/N2 flow ratio, gas pressure and substrate temperature) on the microstructure and properties of CrAlN coatings were systematically studied with scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrum (EDS) and nano-indentation techniques. The results indicated that Ar/N2 flow rate, gas pressure and substrate temperature greatly influenced the microstructure and properties of CrAlN coatings. With Ar/N2 flow ratio of 1, gas pressure of 0.2Pa and substrate temperature of 300°C, the hardness and elastic modulus of CrAlN coating were 34.8GPa and 434.3GPa respectively.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.