Method for preparing a stable aqueous aminopolycarboxylic acid solution composition

The present invention is to provide a stabilized aqueous aminopolycarboxylate solution composition and a method of stabilizing the aminopolycarboxylate through preventing the same from caking. An aqueous aminopolycarboxylate solution composition containing an aminopolycarboxylate represented by the following general formula (1): in the formula, X may be the same or different and represents a hydrogen atom, an alkali metal atom, or an ammonium group, which has a D-form/L-form molar ratio of an aspartic acid skeleton of the aminopolycarboxylate of 1/0 to 0.7/0.3 or 0.3/0.7 to 0/1, has a solid concentration of 25 to 60 mass %, and has a pH value of not more than 11.