The invention relates to the technical fields of foods and chemical industry and particularly relates to a novel method for preparing condensed phosphate solution. The method comprises the steps of selecting a high boiling point solvent as a heating medium, and then, evaporating to dehydrate a phosphate solution to obtain the condensed phosphate solution. The obtained condensed phosphate can be directly used in the process of preparing flavor nucleotide disodium by using inosine and vernine, wherein one phosphoric acid in the condensed phosphate can be cut off and added on a nucleoside under the action of an acid phosphatase. The process provided by the invention has the advantages of few impurities in condensed phosphate, low equipment investment, low comprehensive energy consumption and low production cost.