Abstract: OBJECTIVE To explore the respiratory tract infections in PICU children patients and to provide evidence for the treatment of respiratory tract infections in children. METHODS A total of 1000 cases of critically ill children treated in PICU from Jan. 2011 to Dec. 2014 in our hospital. According to children ages, they were divided into two groups: ≤6-month old group (n=538) and >6-month old group (n=462). The incidence of respiratory tract infections in the two groups were compared, and the distribution and drug resistance of pathogenic bacteria in children with respiratory tract infection were analyzed using VITEK-AMS32 automatic bacterial identification, susceptibility analyzers, matching identification card and Minka drug identification. Respiratory infections in children and antibiotic resistance were analyzed. The results were statistically analyzed by software SPSS 17.0. RESULTS There were 38 cases of respiratory tract infections in the 1000 cases of critically ill children with an infection rate of 3.8%. The respiratory tract infection rate of patients in >6-month old group was 2.2% which was significantly lower than that of ≤6-month old group with an infection rate of 5.2%. The difference has statistical significance (P<0.05). A total of 45 strains of pathogenic bacteria were isolated from the infected children: 25 strains of gram-negative bacteria accounting for 55.6%, 11 strains of gram-positive bacteria accounting for 24.4% and 9 strains of fungi and accounting for 20.0%. Pathogenic bacteria mainly contained Klebsiellapneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans respectively accounting for 20.0%, 13.3%, 17.8% and 15.6%. Gram-negative bacteria were more sensitive to commonly used antimicrobial drugs such as imipenem, ciprofloxacin, amikacin, kanamycin, gentamycin and levofloxacin. Staphylococcus aureus were more sensitive to linezolid and vancomycin. C.albicans were sensitive to amphotericin B, MI miconazole, ketoconazole, itraconazole and nystatin. CONCLUSION The respiratory tract infections rate in critically ill children patients in ≤6-month old group is higher, and the main pathogen is gram negative bacteria