The mucus offish skin epithelium is a vital component in the fish innate immunology，which contains many non - specific  antibacterial activity components，and can resist against diseases under the natural environment. Our research concerned  the antimicrobial activity  of  kidney，spleen，hindgut  and  the   skin mucus   of immune related tissues from Platichthys stellatus.    The  result  showed   that  t!ie extract of   immune related   tissues   from   starry flounder had the   an­ timicrobial activity against Vibrio anguillarum，Vibrio anguillarum，Vibrio parahaemolyticus and Edwardsiella. The antibacterial substance was not sensitive  to  temperature. The antibacterial substance  were   treated   for  10  min  at  37，50，70 and 95 \，and the result showed that the antibacterial activity did not change significantly  treated at   37，50 and 70 \，but  remarkably decreased if treated at 95  The  activity of mucus      was enhanced   in acid  solution，but   was weakened in  alkaline    solution.  Lysozyme  could   weaken  the activity  of mucus， but  trypsin  and protease K could    en­hance the     activity. The  skin         mucus  had the   higher  hemolytic  activity. The identification of gel filtration   chromatogra­phy of antimicrobial  substances     showed that tiie antimicrobial substances of tiie  various tissues may be the  substances witii small molecular weight. [ Chinese Fishery Quality and Standards，2015，5 ( 3 ):63 - 69 ]