L-arginine (350, 550, 650, 700, 710, 720, 725, 730, 740, 750, 800, and 900 mg resp.) was added to 1 g cefepime hydrochloride for injection.The pH, color and clarity were examinedThe optimum range of quantity of L-arginine added to 1 g cefepime hydrochloride for injection is 720-730 mg.According to the result, 725 mg/L-arginine was added to 1 g cefepime hydrochloride for injection in manufacture process.