Abstract: In this study, the single and joint toxicities of 6 wide used and represented antifouling compounds, including 3-(3,4-dichlorophenyl)-1, 1-dimethylurea(Diuron), 2-methylthio-4-t-butylamino-6-cyclopropylamino-s-triazine(Irgarol 1051), triphenylborane pyridine(TPBP), Zinc pyrithione(Zn-Pt), Zinc bis(dimethyl thiocarbamate,Ziram), and Cu²⁺, were examined to promote the toxicity data approaching to the real situations and to provide the optimized compounds adding strategies. The single toxicities against Artemia nauplii were detected with results of descending order of TPBP >Diuron>Ziram> CuSO₄ >Irgarol 1051 >Zn-Pt with LC₅₀ of 0.07, 8.0, 8.2, 9.1, 12.0, and 30.9μg/cm³, respectively. When every two compounds were combined, the joint effects of their toxicities were evaluated by MTI analysis. The results indicated that there were 8 synergetic combinations, including Irgarol 1051/Diuron, Irgarol 1051/TPBP, Irgarol 1051/Ziram, Irgarol 1051/Zn-Pt, Irgarol 1051/CuSO₄, Diuron/TPBP, Ziram/CuSO₄, and Zn-Pt/CuSO₄. Among them, the MTIs of the combinations of Irgarol 1051/Ziram and Zn-Pt/CuSO₄ were detected as high as 2.740 and 5.621, respectively. All 5 Irgarol 1051 involved combinations showed synergistic effects, which indicates that Irgarol 1051 in the marine environments may lead to higher risk than previously evaluated based on the single toxicity data. In addition, 5 antagonistic combinations, including Diuron/Zn-Pt, Diuron/CuSO₄, TPBP/Ziram, TPBP/Zn-Pt, and Ziram/Zn-Pt, were also observed. Those coexistence of antagonistic compounds in same antifouling paints will lead to the reduced antifouling efficiencies, therefore, should be avoided.