The research of probiotics for aquatic animals is increasing with the demand for environment friendly aqnaculture. The probiotics were defined as live microbial feed supplements that improve health of man and terrestrial livestock. Most attempts to propose probiotics have been undertaken by isolating and selecting strains from aquatic environment. These microbes were vibrionaceae, pseudomonads, lactic acid bacteria, Bacillus spp. and yeasts. Some corrunercial products are referred to as probiotics used in eel culture, though they were commercial preparations devised for land animals. This paper focuses on selection of probiotics from bacterial strains which were isolated from intestinal tract of cultured healthy eels （ Anguillla anguilla and A. japonica）, then use the selected probiotics as supplement of eel feed. 477 bacterial strains of intestinal tract of cultured eel were used for testing the antagonistic against Edwardsilla tarda, Vibrio anguillarum Non O1 Vibrio cholera, Acinectobacter lwoffii, Aeromonas hydrophila and Aeromonas sobria etc. commonly eight strains of pathogenic bacteria of of cultured eel, and gelatinase, lipase, amylase, lecithinase, casease and chitinase production. 47 bacterial swains were selected as candidates. Then, by evaluating the BOD value of the 47 strains in the liquid eel-feed-medium, 19 bacterial strains which could effectively using eel feed as their nutrients for growth were selected as candidates. After identification, 5 strains as Pseudomonas cavie, P. stutzeri, P. fluorescens （ 2 strains）, Staphylococcus lentus were pathogenic bacteria to cultured eel, 5 strains were no identification, these isolations were abandoned. Selected one strain from two Bacillus subtilis isolations and two Bacillus pumilus isolations, combined with other isolations, 7 bacterial strains were selected as candidates. By tested the degrade fish meal and tested free amino acid of 7 candidates, strain A40209CDC4 and strain A31009NA were selected as probiotics for supplement of eel feed. By oral administration （A31009NA） and injection infection （A40209CDC4 and A31009NA） test, the results of acute toxicity to European eel showed that there were no toxicity to European eel in 7days at dosage 10^9CFU?mL^-1 concentration of strain A40209CDC4 and strain A31009NA. Strain A40209CDC4 and strain A31009NA used as supplement of formulated eel feed at dosage 10^6 CFU?g^-1, the test eel was cultured at 22 ? 1 ℃, 100% water changed daily for forty days, the digestibility of dry matter and crude protein increased 30.96 and 10.04 percentage of strain A40209CDC4 respectively, and the digestibility of dry matter and crude protein increased 42.96 and 13.11 percentage of strain A31009NA respectively. From all of test items, the selected isolations were suitable used as probiotics for eel. The exploration and application of the selected isolations using as supplement of eel feed were significant.