the present invention provides application of camptothecin and derivatives thereof as antifouling agent , relating to camptothecin . application of camptothecin and derivatives thereof as antifouling agent for facilities in water is provided , wherein the antifouling agent contains camptothecin and / or at least one of its derivatives . the application of camptothecin and derivatives thereof as antifouling agent for facilities in water can be used to prevent attachment of marine or freshwater micro - fouling organisms and / or large fouling organisms to the surfaces of facilities in the sea , lake , river or pool . the antifouling agent may also be used in mixture with other antifouling substance . antifouling method for artificial facilities in water is provided . an antifouling paint for facilities in water is provided . camptothecin and its derivatives have significant inhibitory activity to the attachment of fouling organisms , i . e . having antifouling activity , and can be used to prevent the attachment of fouling organisms on the surfaces of artificial facilities in water . camptothecin and its derivatives have high antifouling activity , good antifouling efficiency , and broad - spectrum antifouling .