We report our clinical exploration experience treating a 6-year-old girl with a postoperative central nervous system (CNS) infection of prolonged invasion with Klebsiella pneumoniae (K. pneumoniae) co-resistant to carbapenems and polymyxin B. Although rational antibiotic therapy and effective source control measures were applied, the infection was not controlled eventually. To understand the mechanism of infection, whole-genome sequencing (WGS) was used to explore the resistance mechanism, and the susceptibility test was used to observe the efficacy of ceftazidime-avibactam (CAZ-AVI) in vitro. It is currently uncertain whether CAZ-AVI could be used as a salvage therapy for pediatric CNS infection. Therefore, we hope to share this case to seek medical help worldwide to treat pediatric CNS infection.