Abstract: For the large-scaled intensive pig farm, the liquid pig feed fermented by the microbe can adjust and control the pH value in pig stomach, and it can also inhibit the growth of microbe and bacteria in the gastrointestinal tract, enhance the digestion ability and improve the nutrient absorption and enzyme activity. Liquid feeding system, controlled by double MCS-80C31, sends feed into mixing tank with weighing sensor according to liquid feed formula, feed nutrient component, pig growth requiring. It accurately and evenly controls liquid feed mixing and fermenting process in the mixing tank and automatically feed different finishing pigs group with the feeding curve. Experimenal results show that the feed conversion ratio and daily weight gain was increased by 6.77% and 9.33%, respectively, by feeding the liquid feed to the finishing pigs, compared with feeding dry feed, and the feeding has a significant effect.