The invention relates to a compound as well as a preparation method and an application thereof, in particular to a preparation method of a novel medicament for inhibiting pestalotiopsis, peronophythora litchii and cylindrocladium parasiticum. Naphthylacetic acid technical, bromoethanol technical and carbendazim technical as synthesis raw materials are subjected to a reaction, and naphthylacetic acid-carbendazim conjugate is obtained and is the final product. The invention also discloses nuclear magnetic resonance structural data, hydrogen spectra and carbon spectra of the novel compound. The compound has good bacteriostatic effects on pestalotiopsis, peronophythora litchii and cylindrocladium parasiticum.