4-Amino-3-hydroxybenzoic acid CAS NO. 2374-03-0 can be used as an inhibitor of anti-HIV infection therapy and diabetes drug Mail2 lard reaction, and it is used as a monomer to prepare lyotropic polymer material polybenzoxazole. As a fine chemical ,4-Amino-3-hydroxybenzoic acid can be used to prepare a series of derivatives using it as a raw material, and can also be used in thermal recording materials and hair dyes.