The invention provides a rice grain miniature engraving method. The method comprises the following steps: full and complete rice grains are screened out; the rice grains are put into acid liquor to be washed and then are washed out through water; the rice grains are added into a steam boiling furnace, and therefore surfaces of the rice grains expand, the temperature of water steam ranges from 80 DEG C to 85 DEG C, the treatment time of the rice grains in the steam boiling furnace ranges from 2.0 min to 3.5 min, and the softening depth of the surfaces of the rice grains is controlled to range from 0.5 mm to 1.2 mm; the rice grains are conveyed to the environment at the temperature of -42 DEG C, the rice grains are subject to heat preservation for 3 min, then, the temperature slowly rises to -15 DEG C for sublimation, the surfaces of the rice grains are subject to freezing drying, then, the temperature slowly rises to the room temperature, and the full surface curing process is controlled to be completed within 15 min; and a conventional engraving method is adopted for miniature engraving. The rice grains are subject to screening, washing, surface half-cooking, surface curing treatment, and removal of powder attached to the surfaces of the rice grains and portions prone to being worn, the surfaces of the rice grains are subject to the process of half-cooking expansion and freezing drying, and therefore the surfaces are more easily engraved, and the condition of edge breakage in the engraving process is reduced.