The present invention discloses a dexamethasone semiantigen and a corresponding artificial antigen. Meanwhile, the invention also discloses a preparation method and application of the dexamethasone semiantigen and the corresponding artificial antigen. The dexamethasone semiantigen is a product shown as formula 1, and the product shown as the formula 1 is connected with a carrier protein to obtain the dexamethasone antigen. The dexamethasone antigen can be applied to the preparation of a dexamethasone specific antibody. The preparation method is simple and feasible, the cost is low, and the yield of the semiantigen is higher. The dexamethasone artificial antigen can produce specific antibodies against dexamethasone by immune animals, can be used for the preparation of ELISA (enzyme-linked immunosorbent assay) detection kits for detection of dexamethasone residues, and has the advantages of being simple, fast, large in processing amount of samples, high in sensitivity, strong in specificity, and the like.