Abstract: OBJECTIVE To analyze secondary antibiotic-associated diarrhea (AAD) in children with severe bacterial infection in pediatrics. METHODS A total of 1342 children with severe bacterial infections treated in pediatrics from Jan. to Dec. 2017 were selected as the research subjects. The incidence of AAD was measured and the pathogens in feces were detected. Age, hospitalization time, antimicrobial use time, white blood cell count, hs-CRP of children with AAD and non-AAD were compared, and multivariate analysis of the factors affecting the occurrence of AAD was conducted. RESULTS 78 cases were diagnosed as AAD among the 1342 children, and the incidence was 5.8%. No Shigella, Salmonella, EPEC, EIEC, ETEC, EHEC bacteria were detected in all children. The positive rate of Candida albicans was the highest, followed by Escherichia coli, and the detection rate of CD was 17.9%. Multivariate analysis showed that age, use of more than 2 kinds of antibiotics, application of the 3rd generation cephalosporins, high white blood cell count, high hs-CRP, complication with damage of important organs, long antibiotics application time and long hospital stay were risk factors of secondary antibiotic-associated diarrhea(P＜0.05); Preventive use of microecological agents was a protective factor(OR=0.631,P＜0.05). CONCLUSION The pathogens of antibiotic-associated diarrhea in children with severe bacterial infections are complex and have many influencing factors. We should pay attention to the prevention of AAD in clinical practice.