The invention relates to a nano-diamond coating cutting tool and the application thereof to mouth rehabilitation ceramic machining. The nano-diamond coating cutting tool is characterized in that (1) the cutting tool is a ball milling cutter, a spiral angle of a spiral groove in a cutting edge of the cutting tool is 30 degrees, and the length of the cutting edge is 2mm; (2) a V-shaped groove is formed in the top of the cutting edge of the cutting tool, a vertical included angle alpha between the V-shaped groove and the center of the cutting tool is equal to 1-5 degrees, an included angle beta is equal to 18-25 degrees, the depth of the V-shaped groove is changed along with the diameter change of the cutting tool, and the depth S value of the V-shaped groove is 10-18 percent of the diameter Phi value of the cutting tool; (3) the cutting edge of the cutting tool is a nano-diamond coating, the diameter of nano-diamond particles is 20-50nm, and the diameter of the head is 2-10mm. When the diameter of the head is less than or equal to 4mm, the diameter of a tool handle is less than or equal to 4mm, and the diameter of a handle part is 4mm; when the diameter of a ball is more than 4mm, the diameter of the handle part is equal to the diameter of the head. When the provided nano-diamond coated cutting tool is applied to pre-sintering ceramic machining for mouth rehabilitation, the feed is 1,400mm/min, and the speed of a main shaft is 25,000rpm. Powder formed by cutting is effectively discharged, the phenomenon of tool breakage is reduced, and the service life is prolonged by 25-30 percent.