Mangroves are special woody plant communities in the intertidal zone of tropical and subtropical coasts.They prove to be a natural microorganisms and new metabolites storage.In the study of mangrove endophytic fungi metabolites,four new compounds,Compounds 1,2,3 and 4,as well as a known octaketide,oytosporone B(5),are isolated from an endophytic fungus,Dothiorella sp.,HTF3.They all show cytotoxic activities.The elucidation of these structures is mainly based on 1D/2D NMR and ESI-MS spectral analyses.