Abstract: The effects of substrate temperature on the growth rate and quality of diamond films by DC arc plasma jet method were studied. It was found that the growth rate and crystallinity of diamond films increased monotonically with the increase of substrate temperature. However, when the substrate temperature increased from 800℃ to 1200℃, the content of non-diamond carbon co-deposited in the diamond films decreased first, and then increased rapidly after reaching a minimum at 1000~1 100℃.