Abstract: The friction and wear behavior of diamond-like carbon (DLC) deposited 40Cr steel are investigated, the anti-corrosion behavior of DLC films is analyzed quantitively.It is indicated that the DLC film can decrease the friction cofficient and roughness of surface of 40 Cr steel obviously.The wear rate of DLC is two orders of magnitude lower than that of 40 Cr steel on the same load and the corrosion rate is much lower in various corrosion solution. The electrode potential,corrosion potential and critical pitting corrosion potential of DLC films are higher than those of 40Cr steel substrate indicating that DLC films can improve the anti-corrosion behavior of 40Cr steel.