The present research aimed to develop a new probiotic product with functions of both lysine high-yielding and strong inhibition on the growth of E. coli O8 by screening and mutation breeding of the Bacillus strains.A total of 112 Bacillus strains were isolated from pig intestine in the present study by traditional culture-based method.The lysine content in the culture supernatant of Bacillus strains was determined by Automatic Amino Acid Analyzer.The inhibition effects of Bacillus strains on the growth of E. coli O8 were determined using an inhibition zone assay.The UV-mutagenesis and s-(2-aminoethyl)-L-cysyeine hydrochloride（AEC）screening was conducted on bacterial strain.The results indicated that there existed large differences for the lysine content of the culture supernatant among different Bacillus strains.The Bacillus subtilis PA105 can effectively inhibit the growth of E. coli O8 and its lysine content in the culture supernatant was up to 0.3 g/L. The UV-mutagenesis and S-(2-aminoethyl)-L-cysyeine hydrochloride（AEC）screening was conducted on B. subtilis PA105.The lysine content in the culture supernatant of the resulting mutant strain B. subtilis PL83 was up to 0.582 g/L.The lysine content in the culture supernatant of the resulting bacterial strain in the present research is increased by almost 100 percent compared with conventional strains.