Abstract: Thirty-two healthy weaned pigs, which have the same breed and breeding level, were randomly divided into 4 groups. The control group fed on basic feedstuff without antibiotics. Group Ⅰ, Ⅱ, Ⅲ fed on basic feedstuff with 12, 15, 18mL／kg of bacillus acidi lactici respectively. After 30 days, their growth performances were measured. The results showed that the diarrhea percentage of control group was significantly higher than those of experiment groups, and group Ⅲ was the lowest. The average daily gain of group Ⅲ was dramatically different from other three groups (P<0.05), and the control group was significantly vary with group Ⅱ. The average daily gain of group Ⅲ was 358g, which was the highest of all, and that of control group was 303g, which was the lowest. The ratio of feedstuff to gain of group Ⅲ was dramatically different from other three groups (P<0.05), and group Ⅱ had little difference with group Ⅰ(P>0.05) while it had significant distinction with control group (P<0.05). The better ratio of feedstuff to gain was group Ⅲ which was followed by group Ⅱ.