Abstract: OBJECTIVE To prepare diclofenac sodium injection with therapeutic concentration and high stability. METHODS Hydroxypropyl-β-cyclodextrin was used to form the inclusion complex with diclofenac sodium. The compounding rate was measured by phase solubility diagram. The optimal antioxidant and sterilization condition were selected. RESULTS The analysis showed the inclusion complex could be formed when the concentration of hydroxypropyl-β- cyclodextrin was more than 0.067 7 mol·L^-1. Monothioglycerol was a suitable antioxidant to stabilize the injection. Filtration should be used for terminal sterilization. CONCLUSION Hydroxypropyl-β-cyclodextrin could increase the aqueous solubility of diclofenac sodium to reach the effective therapeutic concentration. The diclofenac sodium injection prepared was stable enough to satisfy the clinical requirement.