A method for preparing rare-earth polish powder in high cerium nanometer magnitude from rare earth ore concentrate, which is characterized in that the producing steps comprise directly preparing mixed carbonic acid rare-earth from rare earth ore concentrate dense sulphating roasting and infusion with a method of precipitating ammonium acid carbonate, mixing the mixed carbonic acid rare-earth and alkali 0.5-2 parts, heating to 600-800 DEG C to melt the compound, keeping the temperature for 1-4 hours in the molten state, cooling, grinding, then, adding industrial hydrofluoric acid HF>=45% whose adding amount is 10%-20% of the weight of rare-earth concentrate powder, and obtaining oxyfluoride rare earth enriched products, the oxyfluoride rare earth enriched products are grinded, watered, water filtered, mixed in a mixer, then packed into a high-energy ball mill with sieve, and filled with nitrogen, wet powder is ball-abraded with high energy, a high pressure current rotary passage is arranged on the lower portion of a rear sieve of a high-energy ball mill room, the water of sieved powder is dried under the impetus of high speed currents and then baked, and finished polish powder whose powder particle size is <=500nm is obtained.