Actinomycetes are an excellent treasure resource of structurally novel and bioactive natural products with potent medicinal values.The metabolites of the coral-associated Streptomyces sp.rssa1 from South China Sea were investigated.Totally,ten compounds were isolated from the solid fermentation extract using various chromatography methods including silica gel column,ODS reverse gel column,Sephadex LH-20 column and semipreparative HPLC.Their structures were identified as tetramycin A (1),tetramycin B (2),kanglemycin M (3),tryptophandehydrobutyrine diketopiperazine (4),3-indole acetamide (5),N-acetyltryptophan (6),phenylacetic acid (7),N-acetyltyramine (8),benzamide (9),phenylacetamide (10) by NMR,MS data analysis and comparison with previously reported data.The antibacterial,cytotoxic and phosphodiesterase PDE4 inhibition activities of several compounds were screened.The results showed that compound 4 possessed weak inhibitory activity against the growth of Vibrio alginolyticus.Compound 3 displayed cytotoxic activity towards RAW 264.7 cells.No compound showed phosphodiesterase PDE4 inhibition activity at the concentration of 5 μmol/L.