The clarity of famotidine for injection was improved.Different trials were designed to determine the effect of lyophilizing curve, pH of solution, use of mannitol, formulations, vials and stoppers on clarity.Different lyophilizing curves led to differences in clarity.The pH of solution, use of mannitol, formulations, vials and stoppers had little impact on clarity.Clarity of this product is affected by the temperature and time of second sublimation of lyophilizing curve.There is no effect from pH of solution, use of mannitol, formulations, vials and stoppers.It can serve as a reference for mass production