Objective In order to develop the marine organic resource,and based on OSMAC strategy,research anti-tumor activity secondary metabolites from coral-derived bacteria L-4 of the South China Sea.Methods Explore different media to the influence of marine-derived cultivatable microbes by TLC and HPLC.The compounds from the ethyl acetate extracts of bacteria L-4 were isolated by silica gel column,Sephadex LH-20 column chromatography and HPLC techniques.Compounds were identified by the physicochemical properties and spectral analysis (1D,2D NMR and MS et.).Results Different media obviously effect the secondary metabolites,and produce different substances which were not present in the sole cultivate by TLC and HPLC.Fifteen compounds were isolated from the ethyl acetate extracts of marine bacteria L-4 isolated coral of South China Sea.They were identified as cyclo (Trp-Ala),cyclo (Tyr-Gly),Cyclo (Gly-Phe) ,cyclo (Gly-Pro),cyclo (Ala-Val),cyclo (Gly-Ala),Cyclo (Ala-Tyr),Cyclo (Val-Phe),Cyclo (Ala-Phe),Cyclo (Gly-Leu),Cyclo (Ala-Leu),whcih are also cyslo-dipeptide.Four compounds are ongoing.Another one was composed of four amino acids: tyrosine,glycine,serine,alanine by NMR and HR-ESI-MS,and was a new cyclo-tetrapeptide.Conclusions Change marine-derived cultivatable microbes growth media to stimulate more high activity novel structure is worthy of study.All of the compounds were isolated from the marine bacterium L-4 for the first time.