[Objective] Identified six thraustochytrid strains isolated from Shenzhen costal seawater and sediment. Morphological characteristics, life cycle and fatty acid profiles of these strains were studied. [Methods] Thraustochytrid strains were isolated using pine pollen as bait and identified based on 18S rRNA gene sequences. Morphological characteristics were observed using microscope. Nile red staining was used to qualitatively analyze oil content. While GC-MS were used to analyze specific fatty acid profile. [Results] Analysis in 18S rRNA gene revealed that they belong to three genera Aurantiochytrium sp., Schizochytrium sp. and Thraustochytrium sp.. Among these strains, Mn11 and Mn15 were found to produce high level of saturated fatty acid, which is more than 70% total fatty acid. While Mn16 and Sw7 showed high capacity of DHA production with 1.29 g/L and 1.26 g/L DHA yield. [Conclusion] Mn11 and Mn15 strains were suitable for biodiesel production while Mn16 and Sw7 were promising DHA producing strains.