Abstract: Schizochytrium limacinum SR21 is a kind of marine microalgae rich in DHA.The research group that the author joined previously found that SlMYB118 gene of S.limacinum SR21 was closely related to fatty acid synthesis and was a potential transcription factor for DHA synthesis regulation.In this paper,the full-length cDNA sequence of SlMYB118 gene was cloned by PCR and analyzed by bioinformatics method.The results predicted that SlMYB118 protein had an isoelectric point of 8.75,a molecular weight of 84.81 kDa,was localized in the nucleus,and had 106 potential phosphorylation sites.This study laid the theoretical foundation for the subsequent identification of the binding site of SlMYB118 gene,which was a key issue for the transcriptional regulatory mechanism and the establishment of the transcriptional regulatory network related to DHA synthesis.