Objective: To investigate the clinical features, pathogen composition, and prognosis of septic shock in pediatric intensive care units (PICU) in China. Methods: Multi-center retrospective cohort study. A retrospective analysis was conducted on the clinical data of children with septic shock from 10 hospitals in China between January 2018 and December 2021. The clinical features, pathogen composition, and outcomes were collected. Patients were categorized into malignant tumor and non-malignant tumor groups, as well as survival and mortality groups. T test, Mann Whitney U test or Chi square test were used respectively for comparing clinical characteristics and prognosis between 2 groups. Multiple Logistic regression was used to identify risk factors for mortality. Results: A total of 1 247 children with septic shock were included, with 748 males (59.9%) and the age of 3.1 (0.9, 8.8) years. The in-patient mortality rate was 23.2% (289 cases). The overall pathogen positive rate was 68.2% (851 cases), with 1 229 pathogens identified. Bacterial accounted for 61.4% (754 strains) and virus for 24.8% (305 strains). Among all bacterium, Gram negative bacteria constituted 64.2% (484 strains), with Pseudomonas aeruginosa and Enterobacter being the most common; Gram positive bacteria comprised 35.8% (270 strains), primarily Streptococcus and Staphylococcus species. Influenza virus (86 strains (28.2%)), Epstein-Barr virus (53 strains (17.4%)), and respiratory syncytial virus (46 strains (17.1%)) were the top three viruses. Children with malignant tumors were older and had higher pediatric risk of mortality (PRISM) Ⅲ score, paediatric sequential organ failure assessment (pSOFA) score (7.9 (4.3, 11.8) vs. 2.3 (0.8, 7.5) years old, 22 (16, 26) vs. 16 (10, 24) points, 10 (5, 14) vs. 8 (4, 12) points, Z=11.32, 0.87, 4.00, all P<0.05), and higher pathogen positive rate, and in-hospital mortality (77.7% (240/309) vs. 65.1% (611/938), 29.7% (92/309) vs. 21.0% (197/938), χ2=16.84, 10.04, both P<0.05) compared to the non-tumor group. In the death group, the score of PRISM Ⅲ, pSOFA (16 (22, 29) vs. 14 (10, 20) points, 8 (12, 15) vs. 6 (3, 9) points, Z=4.92, 11.88, both P<0.05) were all higher, and presence of neoplastic disease, positive rate of pathogen and proportion of invasive mechanical ventilation in death group were also all higher than those in survival group (29.7% (87/289) vs. 23.2% (222/958), 77.8% (225/289) vs. 65.4% (626/958), 73.7% (213/289) vs. 50.6% (485/958), χ2=5.72, 16.03, 49.98, all P<0.05). Multiple Logistic regression showed that PRISM Ⅲ, pSOFA, and malignant tumor were the independent risk factors for mortality (OR=1.04, 1.09, 0.67, 95%CI 1.01-1.05, 1.04-1.12, 0.47-0.94, all P<0.05). Conclusions: Bacterial infection are predominant in pediatric septic shock, but viral infection are also significant. Children with malignancies are more severe and resource consumptive. The overall mortality rate for pediatric septic shock remains high, and mortality are associated with malignant tumor, PRISM Ⅲ and pSOFA scores.