Abstract: OBJECTIVE To investigate distribution characteristics and changes of drug resistance of pathogenic bacteria in PICU patients, so as to provide basis for clinical infection control and choice of antimicrobial agents. METHODS A total of 5358 cases of patients in PICU from Jan.2013 to Dec.2015 were analyzed, and the species of the pathogenic bacteria and their resistance to antibiotics were analyzed. SPSS 17.0 software was used for statistical analysis. RESULTS Sputum was the main source of 617 strains of detected pathogenic bacteria, and 379 strains were detected from sputum, accounting for 61.43%. The drug resistant rates of Staphylococcus aureus and coagulase negative Staphylococcus, MRSA and MSS to teicoplanin and vancomycin were 0. The drug resistant rates of Klebsiella pneumonia to aztreonam, ampicillin/sulbactam, chloramphenicol, ceftazidime, cefotaxime, and piperacillin/tazobactam increased from 2013 to 2014, and decreased from 2014 to 2015, and differences were significant (P＜0.05). CONCLUSION Gram-negative bacteria were the main pathogens in PICU, and the drug resistant rates of common pathogens to some antimicrobial agents have changed.