Dexamethasone sodium phosphate belongs to adrenocortical hormone drugs, which can stabilize lysosomal membrane and reduce the release of lysosomal hydrolase; It can inhibit the production of bradykinin, 5-hydroxytryptamine and prostaglandin, increase the stability of mast cell granules and reduce the release of histamine; Constrict blood vessels, inhibit the migration of leukocytes and macrophages outside blood vessels, so as to have anti-inflammatory effect. It can exert immunosuppressive effect by inhibiting the function of macrophages. It can inhibit the formation of fibroblasts, prevent corneal scar, reduce scar formation and protect vision when used in trauma. It can inhibit or reduce the formation of neovascularization in corneal and conjunctival diseases. Local application can reduce rejection and scar formation in corneal transplantation and myopic surgery. It is clinically used for the treatment of autoimmune diseases, allergies, inflammation, rheumatism, asthma, ophthalmology and dermatology.