The invention relates to a feed additive, in particular to a pig feed additive. The additive can significantly enhance the growth and production performance of pigs, improve the nutrition and health of pigs under various emergency states, reduce the diarrhea rate and death rate of pigs, lower the feed-meat ratio, and increase the feed conversion rate. The compound feed additive is prepared from raw materials gamma-aminobutyric acid, tauroursodeoxycholic acid, resveratrol, rabdosiae herba, pyrola, common scouring rush herb, Xuanzhou papaya, Cynanchum glaucescens, Chinese mahonia leaf, Fructus Toosendan, Patrinia heterophylla, Nelumbo nucifera Gaerth, Pouzolzia zeylanica herb with root, Lysimachia clethroides Duby, bacillus licheniformis freeze-dried powder, clostridium butyricum freeze-dried powder, and a carrier, and the carrier is a mixture of corn flour and soybean meal.