Background: To investigate the predictive value of predictive value of procalcitonin (PCT), 8-iso-prostaglandin F2α (8-iso-PG-F2α) and pulmonary surfactant-associated protein D (SP-D) for the development of severe pneumonia in children. Methodology: Children with severe pneumonia were selected as the pneumonia group, and children with non-pulmonary respiratory diseases were selected as the control group. PCT, 8-iso-PGF2α, and SP-D were compared between the pneumonia group and the control group at admission; PCT, 8-iso-PGF2α, SP-D, and Acute Physiology and Chronic Health Evaluation (APACHE-II), Pediatric Critical Illness Score (PCIS) and Clinical Pulmonary Infection Score (CPIS) scores were compared between children with severe pneumonia with different pathogen infection types and different prognostic outcomes; and the correlation between APACHE-II, CPIS, and PCIS scores and PCT, 8-iso-PGF2α, and SP-D levels was analysed in children with severe pneumonia. Results: PCT, 8-iso-PGF2α and SP-D in pneumonia group were higher than those in control group. PCT, 8-iso-PGF2α, SP-D, APACHE-II, CPIS, and PCIS were lower in good prognosis children than in poor prognosis children. APACHE-II, CPIS, and PCIS scores were positively correlated with PCT, 8-iso-PGF2α, and SP-D levels in children with severe pneumonia (P < 0.05). Conclusion: PCT, SP-D and 8-iso-PGF2α levels relate to pathogen type, illness severity and prognosis in children with severe pneumonia. They can aiding early evaluation. Keywords: severe pneumonia in children; procalcitonin; 8-isoprostane F2α; pulmonary surfactant-associated protein D; disease assessment.