▎ 摘　　要

NOVELTY - The method involves forming a diamond table layer (1) with a diamond electric conduction channel (2). A photoresist cover is removed from the diamond electric conduction channel and a source part (6). A position of a drain (7) is formed with the photoresist cover. A graphene (4) is covered on a diamond surface. Ohmic contact metal is deposited on the graphene. The ohmic contact metal are selected from a group consisting of ruthenium, silver, osmium, iridium, platinum, gold, titanium, chromium, germanium, nickel, tungsten, copper, cobalt and iron. USE - Diamond device preparing method. ADVANTAGE - The method enables ensuring simple structure, reducing ohm contact metal resistance of a diamond device and increasing diamond property. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view illustrating a diamond device preparing method. Diamond table layer (1) Diamond electric conduction channel (2) Graphene (4) Source part (6) Drain (7)