The invention discloses a preparation method of a boron-nitrogen co-doped nano-based an oriented diamond film. The preparation method comprises the following steps: by taking a heater CVD (Chemical Vapor Deposition) device as deposition equipment, adding boron-nitrogen-containing compounds into a conventional hydrogen and acetone reaction system to form a co-doped system; adjusting the reaction technical parameters; preparing the film where diamond particle particles and oriented diamond particles co-exist. The method is simple in process flow. The obtained film has the characteristics that the film has the surface which is leveler than a randomly oriented micron order diamond film, high and uniform wear resistance, easiness in polishing, low internal stress, high adhesive force of the film base and the like.