A preparation method of a 
diphenyl ether compound and application of the compound as a natural 
marine organism antifouling agent. The preparation method is as below: culturing marine 
fungus Aspergillus sp. (HM535361) in a 
fungus culture medium; conducting 
fermentation culture on the fungi in a 
fermentation medium; then soaking the 
fermentation products with 
methanol; conducting decompression concentration to obtain a 
methanol crude extract; suspending the extract in water; extracting the extract with 
ethyl acetate, conducting vacuum concentration on the extract and conducting 
chromatographic separation; and concentrating the eluent to obtain four colorless or light 
red oil, 4-methoxycarbonyl-diorcinol, 3, 3 '-O-dimethyl-violaceol-I, cordyolC and diorcinol. The invention provides an environment-friendly natural 
marine organism antifouling agent, which is characterized by using the 
diphenyl ether compound as an effective ingredient. The antifouling agent can be used for the prevention and treatment of 
marine organism biofouling caused by attachment of barnacle 
Balanus Amphitrite larvae, and has the advantages of high efficiency and 
low toxicity. The 
raw material can be obtained from 
mass production by fungal fermentation, and is not subjected to 
resource constraints; therefore, the invention has wide application prospect.