Abstract: The purpose of detection of bacterial-polysaccharide on the immune regulation on grass carp。We can use phenol water method to get polysaccharides from E. coli and Agrobacterium tumefaciens cell wall Injection of grass carpdetermination the number of leukocyte of blood ,the vitality of peroxidase in Liver、 kidney、spleen、serum and mucus The results of subjects are the number of grass carp in the leukocyte, serum antibody titer and peroxidase activity have markedly improvedConclusion is E.coli and Agrobacterium tumefaciens coarse polysaccharide have strong immune on grass carp