The invention discloses a loxoprofen sodium coating agent smeared on the surface of skin, relieve and cure rheumatoid arthritis, osteoarthritis, lumbago, scapulohumeral periarthritis, and diseases of shoulders, necks and wrists, and a preparation method of the loxoprofen sodium coating agent. The loxoprofen sodium coating agent comprises chitosan and glycerol, wherein chitosan is a deacetylation product of crustaceans, has favorable biocompatibility, film-forming property, bacterium resistance, inflammation resistance and hemostasis, and serves as a favorable auxiliary material for preparation of gelata; glycerol is taken as a plasticizer and humectant, and used for enabling a film to be high in elasticity and low in fracture possibility, and enhancing the percutaneous absorption of medicine; the coating agent made of glycerol and loxoprofen sodium can be used for overcoming the first pass effect of a liver and gastrointestinal tract effect, improving bioavailability and enhancing curative effect through local skin application. The coating agent has the advantages that the effect taking period is short; the effect is durable; the spreadability and the adhesive force are high; skin irritation is avoided; the drug delivery is convenient. The preparation method is relatively reasonable; the specificity of a content determination method is high; the result is accurate; the standards can be used for controlling the quality of the coating agent.