The invention provides an acid double salt of cefdinir. The acid double salt is obtained by reacting cefdinir with acid and alkali metal element or ammonium (including ammonia) compound or with acid salt. The cefdinir sulfate double salt is prepared when acid or acid salt is sulfate. The cefdinir phosphate double salt is prepared when acid or acid salt is phosphate. The cefdinir acid double salt of the present invention has the obvious advantages of good solubility and high bioavailability, and can be prepared into oral solid preparation or injection. The cefdinir acid double salt has the following structural general formula.