Abstract: Using sodium alginate as the sole carbon source, four bacteria with high productivity of alginate lyase were obtained from samples collected in mangrove, Tianya Haijiao, Li'an Town and seaweed factory of Hainan Province, China.The alginate lyase activity in the medium was measured according to the method of dinitrosalicylic acid when the four bacteria were cultivated in the alginate medium.As a result, when the maximum enzyme activity was reached, alginate lyase activity in the medium of strain S20 was similar to that of strain W14 (0.23⁰.27U /mL) , lower than that of strain E03 (0.58U /mL) , and higher than that of strain W13 (0.13U /mL) .However, the enzyme production rules of four bacteria showed significant differences.Based on the morphological properties and phylogenetic analysis of 16S rDNA, the strain E03 clustered with the genus Pseudomonas, the strains W13 and W14 grouped within the genus Vibrio, and the strain S20 classified as the genus Flavobacterium.