Abstract： Objective To investigate, purify, screen and identify antimicrobial activities of the strains of cuhurable microorganisms from gills, stomachs or intestines. Methods A total of 452 cuhurable microorganisms and 36 strains were isolated from gills, stomachs or intestines of Cetorhinus maximus (Basking shark), of which 5 strains were from gills and 31 strains were from stomachs or intestines. In all, there were 7 strains of fungi (19%), 1 strain of actinomycetes (3%) and 28 strains of bacteria (78%). Molecular identification and classification of 15 isolates based on 16S rRNA sequences indicated that they belonged to the Bacillus, Brevundimonas, Staphylococcus, Staphylococcus xylosus, Bacillus pumilus. Antibacterial activity was screened for the cuhurable bacteria. Results Laboratory experiments revealed that in total 23 strains were isolated from gills, stomachs or intestines, and 15 strains showed antimicrobial activities against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginose, Enterobacter aerogenes, Candida albicaus (with the method of agar piece and disk paper tests), accounting for 65% of the isolated strains. They belonged to Bacillus (5 strains), Staphylococcus (6 strains), Brevundimonas (2 strains), and Psychrobacter (2 strains) respectively. Conclusions The isolation and purification of symbiotic microorganisms from gills, stomachs or intestines of Cetorhinus maximus could be realized via routine microbiology. Results indicated that 50% of the isolated strains showed bacteriostatic effects to various degrees. There is great probability that active antimicrobial substances from these strains might be found through further research.