Objective To evaluate the clinical value of procalcitonin/albumin (PCT/ALB) combined with C-reactive protein/albumin (CRP/ALB) in predicting necrotizing pneumonia due to Streptococcus pneumoniae infection in children. Methods Clinical data of children with Streptococcus pneumoniae necrotizing pneumonia (SPNP) or Mycoplasma pneumoniae necrotizing pneumonia (MPNP) admitted to the pediatrics in a hospital between January 2018 and December 2020 were analyzed retrospectively. Baseline data and peripheral blood laboratory indicators between SPNP group and MPNP group were compared. Urine creatinine (UCr), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels of child patients were measured. Results 272 children with SPNP and 280 children with MPNP were included. Children with SPNP had lower average age, longer duration of fever, longer length of hospital stay, and higher incidence of hypoxemia than those with MPNP, with statistically significant differences (all P < 0.05). Serum CRP, PCT levels, as well as PCT/ALB and CRP/ALB ratios of children with SPNP were all higher than those with MPNP, while ALB level was lower. Differences were all statistically significant (all P < 0.001). UCr, AST, and ALT levels of children in SPNP group were higher than MPNP group, difference were all significant (all P < 0.05). Multivariate logistic regression analysis showed that PCT, CRP, PCT/ALB, and CRP/ALB were independent risk factors for SPNP (P < 0.05), while ALB was an independent protective factor (P < 0.05). The area under the curve (AUC) for PCT/ALB and CRP/ALB in predicting SPNP were 0.898 and 0.921, respectively, and the combined AUC was 0.961. Conclusion It should be alert to the development of children SPNP when PCT/ALB >0.15 and CRP/ALB >3.84.