4 dithiodipropionamides and 4 corresponding trithiodipropion- amides were synthesized by methyl acrylate and amine, and detected by Mass spectrometer, NNR spectrometer and infrared spectrometer. Compared with dithiodipropionamides, the bioassay results of Escherichia coli and Staphylococcus aureus showed that, the trithiodipropionamides possessed better antibacterial activities, and the minimal inhibitory concentration values to the two bacteria of N,N-di-methyl-trithiodipro- pionamide(2a) and N,N-di-ethyl-trithiodipropionamide(2b) reached about 0.03 mg/mL. The study of their antifouling properties submerging in the ocean for a year showed that, all compounds displayed good antifouling property, 2a and 2b displayed the best.