Abstract: Pediatric community-acquired pneumonia (CAP) is a major infectious disease threatening global child health. Its extrapulmonary complications can involve multiple systems, including the digestive, neurological, cardiovascular, hematological, and skin/mucous membrane systems, significantly increasing the risk of progression to severe illness and even death. The pathogenesis of extrapulmonary complications in pediatric CAP is complex and diverse, involving direct pathogen invasion, immune-mediated injury, inflammatory cytokine storm, and microcirculatory disorders, among which the interaction between immunity and inflammation is a core link. The pathogenic mechanisms vary among different pathogens, and the mutual promotion of immune-mediated injury and inflammatory cytokine storm is a central pathological process leading to multisystem extrapulmonary complications in severe CAP. Among digestive system complications, liver injury is the most common, with warning indicators including IL-1 > 28.35 pg/mL, IL-6 > 24.9 pg/mL, and CRP > 34.6 mg/L, while specific indicators exist for different pathogens (e.g., Mycoplasma pneumoniae, Chlamydia psittaci). Regarding nervous system complications, encephalitis, encephalopathy, and epileptic seizures are frequently observed, with warning indicators including neurofilament light chain (NFL), cerebrospinal fluid lactate, D-dimer, and lymphocyte count. Cardiovascular system complications are dominated by myocardial injury (incidence approximately 30.1%), with warning indicators including IL-6 ≥ 258.64 pg/mL, CRP ≥ 14.27 mg/L, and NLR ≥ 2.41; novel biomarkers such as sST2 and cfDNA also have value. Severe hematological complications, such as disseminated intravascular coagulation (DIC) and hemophagocytic lymphohistiocytosis (HLH), have warning indicators including LAR ≥ 8.08 and triglycerides > 3.02 mmol/L. Skin and mucous membrane lesions are mostly associated with Mycoplasma pneumoniae infection, presenting as rash and mucositis. At present, the warning indicators still require validation through multicenter studies with large samples, and most studies focus on Mycoplasma pneumoniae. In the future, comparative studies on complications caused by multiple pathogens and multi-omics research should be strengthened to establish a standardized assessment system.