Objectives The effects of adding lactic acid bacteria to feed on the growth performance and immune performance of broiler chickens were evaluated to provide scientific basis for improving the efficiency of farming poultry. Methods 300 healthy 1-day-old broiler chickens with an average body weight of (44.3 ± 0.4) g were randomly divided into three groups including the control group fed with maize-soybean basic diet, the experimental group Ⅰ supplemented with 0.1% locally isolated lactic acid bacteria concentration of 3×10⁸ CFU/g, and the experimental group Ⅱ supplemented with 0.1% commercial lactic acid bacteria concentration of 1×10⁸ CFU/g. Each group had four replicates, with 25 chickens in each replicate. The experimental period was 42 days. The body weight, feed intake and feed conversion rate (FCR) at different ages, and immune performance at 42 days of age of each group of broiler chickens was measured. Results Compared with the control group, the body weight of broiler chickens in the experimental group Ⅰ and Ⅱ at 42 days of age significantly increased by 109.80 and 109.29 g, respectively. The feed conversion rate in the experimental group Ⅱ significantly increased during the whole feeding cycle. The antibody titers against Newcastle disease virus in the experimental group Ⅰ and Ⅱ increased significantly by 0.68 and 0.82, respectively, and lymphocytes increased significantly by 1.13% and 1.18%, respectively. Conclusions Adding lactic acid bacteria to the feed for broiler chickens can improve the body weight, feed conversion rate, and the immune performance of broiler chickens.