The appropriate salt was used for azithromycin for injection.Eight different kinds of acid react to azithromycin to obtain corresponding azithromycin salt solutions and freeze-dried products for injection.The pH, initial stability and hepatic toxicity test in animals were performed.The solutions of glutamic acid, lactic acid, tartaric acid, and aspartic acid with azithromycin were stable and its pH was in proper range.The pathol. studies revealed that the favorable salts were glutamate, citrate, aspartate, sulfate and hydrochloride, followed by dihydrogen phosphate, lactobionate and tartrate.Glutamic acid and aspartic acid are the appropriate acid for the preparation for azithromycin for injection.