A marine bacterium MWYL1, originally isolated from the roots of Spartina anglica growing in a salt marsh near seaside, was identified as a member of the genus of Marinomonas via morphology characterization、physiological test and 16S rDNA sequencing and Blast analysis. The strain was short, rod, gram-negative, grew aerobically and optimally at 28℃. The analysis of 16S rDNA sequence suggests that the sequence similarity values are 97% and 95% with Marinomonas pontica and Marinomonas dokdonensis, respectively. One fosmid clone producing melanin was directly isolated by plating from the genomic library of Marinomonas MWYL1.The novel functional gene cluster involved in melanin biosynthesis was screened after subcloning and sequencing of the 14kb insert in pUC18, further more, the putative functional genes was preminary analyzed using bioinformatics.