Objective:To summarize the clinical features and treatment of pneumocystis jirovecii pneumonia(PCP) in children with non-human immunodeficiency virus(HIV) infection.Methods:A retrospective study was performed on seven cases of severe PCP children with non-HIV infection who were admitted to PICU of The University of Hong Kong-Shenzhen Hospital and PICU of Xianyang Rainbow Hospital from May 1, 2015 to May 1, 2021.The risk factors, clinical manifestations, laboratory results, pulmonary radiological features, treatment and outcomes were observed.Results:Seven children with PCP, including four males and three females, aged from 13 months to 85 months[(42.4±26.8) months], were all associated with underlying diseases, and most of which was hematological malignancies.Six children had a history of using TMP-SMX for PCP prevention, but four of them stopped by themselves and infected PCP in 2 to 4 weeks.All children had hypoxic respiratory failure, whose OI was 30.6±3.4, and presented with fever, dry cough, progressive dyspnea but no lung rales in the early stage.LDH[(745.7±317.0) U/L] and β-D-glucan[(513.8±225.0) pg/mL] increased in all patients.Chest CT showed diffused interstitial changes in bilateral lung fields associated with multiple exudative lesions.Among the anti-Pneumocystis Jirovecii treatment regimens, all cases began the treatment in the first three days during the admission, five cases were treated with intravenous TMP-SMX, and two cases were treated with oral TMP-SMX + caspofungin, with a course of 21 days.All children were also treated with glucocorticoid at the same time.Three days after the treatment of PCP, two children were worsened and one of them died, while another one started to recover on the 6th day of the regimen.The remaining five cases began to show clinical improvement after 3~7 days of PCP treatment.Finally six children were cured and one was died.Conclusion:PCP infection of children without HIV has high risk of destruction in immune system.TMP-SMX can prevent PCP effectively.In the severe PCP cases, early commencement of intravenous TMP-SMX can reduce the mortality rate.In the absence of intravenous TMP-SMX, oral TMP-SMX can be used with caspofungin.