40Cr steel substrate was coated with TiAlN/TiN films by multi-arc ion technology. The effect of technical elements on the surface and micro hardness of TiAlN/TiN films had been studied with metallographic microscope, SEM and micro hardness instrument. The results show that the negative bias and the target current have marked influence in performance of TiAlN/TiN films. The content of Ti and Al in films becomes lower and lower when the negative bias becomes higher and higher. The content of Ti/Al of films increases when the target current increases. The micro hardness increases firstly and then drops with the increase of negative bias or the target current.