Abstract: Cr-Cu-N films were deposited using low energy ion beam assisted magnetron sputtering (IBAMS).The effects of copper and bombardment energy on structure,hardness and fracture toughness of the films were studied.The added copper had no obvious effects on the film structure and hardness at same bombardment energy of 400eV.But added copper was beneficial to improvement of the film fracture toughness.When the ion bombardment energy was increased from 400eV to 800eV,the film structure was changed remarkably and its fracture toughness and hardness were improved further.