The present disclosure provides a method of preparing highly pure lithium carbonate from brine. The method includes adding an adsorbent to the brine, from which the magnesium ions Mg2+ have been removed, to adsorb lithium ions Li+ to the adsorbent, followed by providing the adsorbent having the lithium ions Li+ adsorbed thereto to a strong acid solution to desorb the lithium ions Li+ from the adsorbent; enriching the strong acid solution in which the lithium ions Li+ are desorbed from the adsorbent; and obtaining lithium carbonate Li2CO3 through chemical reaction between the lithium ions Li+ in the enriched solution and a carbonate precursor.