The invention discloses a preparation method of a high-hardness conductive carbon-based thin film. The preparation method of the high-hardness conductive carbon-based thin film comprises the steps ofplacing an ultrasonically cleaned conductive metal workpiece in a vacuum chamber of a vacuum coating device, and carrying out ion etching and activating; then adopting a bipolar pulse direct-current power supply, sequentially passing through a Cr metal target and a WC target, and forming a Cr-WC transition layer; preparing a hydrogen-containing amorphous diamond-like coating on the Cr-WC transition layer; and rising the temperature to 430 to 600 DEG C in a heat treatment device, preserving heat, and obtaining the high-hardness conductive carbon-based thin film. According to the preparation method of the high-hardness conductive carbon-based thin film provided by the invention, in the diamond-like coating (DLC), the content of sp3C-C is high, high hardness is obtained, meanwhile, the conductivity is reduced, and the diamond-like coating/carbon-based thin film with high adhesion, high hardness and conductivity equivalent to graphite is obtained.