The aims of this study were to determine the effects of probiotic liquid as a feed additive on productivity, microflora balance, enzym activity, number and surface of intestinal villi of the broiler. A laboratory study with a Complete Randomized Design (CRD) on 144 Day Old Chicks (DOC) Lohman strain was conducted. The treatment was the basal feed without the addition of liquid probiotic (P0); basal feed with 0,2 v/w liquid probiotic (P1); basal feed with 0,4 v/w liquid probiotic (P2) and basal feed with 0,6 v/w liquid probiotic (P3). A liquid probiotic containing the composition of Lactobacillus sp. 1,4x10 10 cfu/mLl. Data were analyzed using a CRD followed by the Duncan Multiple Range Test. The results showed that liquid probiotic (Lactobacillus sp.) as food additive give the significant effect (P<0,05) to the number of intestinal villi, showed no significant effect (P>0,05) to protease and lipase activity. It`s showed a significant effect (P<0,01) to total plate count (TPC) of lactid acid bacteria, Salmonella sp., Eschericia coli, the surface of intestinal villi. The result was concluded that the higher concentration of liquid probiotics in feed the higher microflora balance, protease and lipase activity, number and surface of intestinal villi. Decreasement of Salmonella sp. and Eschericia coli TPC. A liquid probiotic (Lactobacillus sp.) 0.6 v/w in feed was suggested to produce the higher performance.