A pleuromutilin derivative having a 2-amino phenyl mercaptan side chain as well as a preparation method and application thereof are provided. The derivative has a structure represented by formula 2 or formula 3, wherein, R1, R2 and R3 are each independently selected from a hydrogen atom, hydroxyl, amino, sulfydryl, hydroxymethyl, amine methyl, nitro, halogen, trihalogenated methyl, methyl, natural amino acid acylamino and C1-6 alkoxy. The plueuromutilin derivative in the disclosure has good activity of inhibiting drug-resistant staphylococcus aureus and mycoplasma, and is especially suitable for preventing and treating infectious diseases caused by human or animal mycoplasma or drug-resistant staphylococcus aureus or multidrug resistant bacteria as a novel antibacterial drug.