Abstract: As a promising electrical material,CVD diamond with the unique chemical properties is difficult to be etched and fabricated.In the paper,for the purpose of finding a suitable etching material,a certain thickness of polycrystalline diamond films were synthesized in silicon by microwave plasma chemical vapor deposition（MPCVD）and then under the hydrogen plasma and the graphitization effect of dissolved carbon material-Fe,Co,the corrosive action of Fe,Co on the surface of diamond film was investigated.After etching the diamond films surface,the samples were cleaned with mixed acid,then heated in the hydrogen plasma.The cleaned surface was observed with scanning electron microscopy under a secondary electron mode.The corroded surface of the diamond films were characterized by Raman spectroscopy.The results indicated that the corrosive effect of these dissolved carbon metals on the diamond films is clear,with Fe having the largest effect,after the etching of the diamond films,the non-diamond-like carbon left on the diamond films surface are cleaning for the further processing,the high quality which can be comparable with the original quality of diamond is obtained.