Abstract: This study was aimed to study effects of zinc oxide-free diet on performance of weaned piglets.A total of 180 Duroc × Landrace × Yorkshire weaned piglets weighing about 7 kg were randomly divided into three groups,two replicates in each group（n = 30）.The piglets in the control group were fed with diet added zinc oxide at a level of 2 000 mg/kg and limestone powder at a proportion of 0.55%.The piglets in the experimental group Ⅰwere fed with diet added limestone powder at a proportion of 0.55% and enteric coated zinc preparation at a level of 500 mg/kg,while those in the experimental group Ⅱ were fed with diet added organic acidifier compound calcium at a proportion of 0.385% and acidifier added at a proportion of 0.15%.The results showed that organic calcium（Lishengbao） which substituted zinc oxide and limestone powder reduced pH values in gastrointestinal tract,inhibited growth and reproduction of harmful bacteria,decreased rate of diarrhea in the weaned piglets,and prevented diarrhea which was achieved by adding zinc oxide.Therefore,the organic acidifier compound calcium and acidifier can effectively zinc oxide and limestone powder and can promote the healthy development of piglets.