Abstract: Diamond-like carbon, DLC coating is a kind of metastable film mixed with sp³ and sp².Because of its excellent mechanical properties, low friction coefficient, superior wear resistance, DLC coatings are widely used in petroleum, aerospace, automotive parts, medicine and optical fields.Due to the large interior stress in DLC coatings, the thickness of the DLC coating is limited, which yields the failure in the tribology behavior and greatly limits the application of DLC coatings in some field.The structure characteristic and main preparation methods were summarized.The research progress of decreasing the internal stress of DLC coating were summarized, and the existing problems in the research were summarized.