A silicon interlayer was introduced between the DLC films and 202 stainless steel substrate using a medium frequency magnetron sputtering. The adhesion was evaluated by the scratch tests and wear tests together. Two main parameters in the deposition process of Si interlayers, i.e. the sputtering current and pulse bias voltage, were optimized respectively, and the action mechanisms were discussed as well. Moreover, a special treatment with the purpose of forming a complete graded intermixed Si-Fe interface was designed to improve the adhesion strength further. DLC films with good adhesion strength were deposited on 202 stainless steel substrates using a silicon interlayer.