Disclosed is a method of producing high-purity lithium carbonate from low-purity crude lithium carbonate. The method includes: (a) producing crude lithium carbonate slurry by mixing crude lithium carbonate having a polycrystalline state and a size of 20 to 200 μm with water; (b) carbonating and dissolving the crude lithium carbonate slurry; (c) performing primary solid-liquid separation to obtain a filtrate; (d) adding soluble barium salts to the filtrate to deposit barium sulfate; (e) performing secondary solid-liquid separation for the filtrate containing the deposited barium sulfate to obtain a filtrate; (f) mixing lithium carbonate seed crystals with the filtrate obtained from the secondary solid-liquid separation and precipitating lithium carbonate dissolved in the filtrate on surfaces of the lithium carbonate seed crystals to produce high-purity lithium carbonate slurry containing high-purity lithium carbonate by controlling a particle size; and (g) carbonating the high-purity lithium carbonate slurry to produce high-purity lithium carbonate.