The present application discloses a composition of a butyrate or a derivative thereof and benzoic acid, preparation method and use as a feedstuff additive thereof, wherein the composition comprises 5 wt% to 50 wt% of the butyrate or the derivative of butyric acid, and 50 wt% to 95 wt% of the benzoic acid or benzoate. The benzoate and butyrate dissociate into acidic molecules when they enter into animals' bodies. The butyric acid stimulates parietal cells to grown and the parietal cells produce hydrochloric acid, which thereby reduces the pH value in the stomach. Benzoic acid can inhibit facultative anaerobes such as Lactobacillus and butyric acid-producing anaerobic bacteria in the stomach, rendering the two floras become predominant microflora, and therefore produce more endogenous organic acids such as lactic acid and butyric acid. These acids are beneficial to gastrointestinal health and animal growth. As a result, a synergy effect of the two components in the composition is achieved.
