Disclosed herein is a method for preparing an aqueous solution of high-concentration calcium phosphate, the method comprising the steps of: preparing an acidic aqueous solution using an acidic chelating agent; and dissolving a calcium phosphate-based compound in the acidic aqueous solution, and then adding a pH-adjusting agent to the acidic aqueous solution to adjust the pH of the acidic aqueous solution. The disclosed aqueous solution does not form a precipitate after neutralization so that it can be used in various calcium-containing products, including foods, drugs, or quasi-drugs.