Abstract: The extracellular products of the causative virbio were isolated from “red spotting” diseased sea urchin Strongylocentroyus intermedius using cellophane plate technique. The products showed amylase, caseinase, gelatinase, and lecithinase activities and pathogenic to the sea urchin. The total protein level and protease activities of extracellular products under different temperatures showed that pathogenicity of extracellular products was influenced by temperature. The extracellular products and lipopolysaccharide led to the symptom of the “red spotting” disease in the sea urchin. Active unit of extracellular products influenced its infectivity but active period did not affect the infectivity. Action unit and time of lipopolysaccharide influenced the infectivity. The extracellular products and lipopolysaccharide of the causative virbio are important fractions which caused the “red spotting” disease in the sea urchin .