Literature retrieval were conducted in PubMed， EMbase， Web of Science， Cochrane Library and China National Knowledge Internet（CNKI）databases. The retrieval period was from the establishment to March 2021. The clinical studies of patients with SCLC including limited stage SCLC （LS-SCLC） and extensive stage SCLC（ES-SCLC） received platinum-based first-line chemotherapy. Meta-analysis was performed on the literatures that met the inclusion and exclusion criteria by STATA 14.0 software， and the prognostic effects of NLR and PLR in the SCLC patients with different disease stages and pathological types were observed.

A total of 1 012 literatures were retrieved. Finally， eleven studies encompassing 3 634 SCLC patients were included. The combined outcomes demonstrated that the overall survival（OS）［hazard ratio（HR）=1.45， 95%confidence interval（95%CI）： 1.26－1.67，P<0.01］ and progression-free survival（PFS）（HR=1.53，95%CI：1.29－1.82，P<0.01） of the patients in high NLR group were lower than those in low NLR group， while there was no difference in the OS between high NLR group and low NLR group（HR=1.17， 95%CI：0.87－1.56，P=0.293）. In subgroup analysis， the OS in higher NLR group in different stages，different pathological types， different regions， analysis modes，and NLR cutoff value≥4 in subgroups were lower than those in lower NLR group（P<0.05）；the OS in LS-SCLC and PLR cutoff value<160 patients in higher NLR group were lower than those in lower PLR group.

In the SCLC patients received platinum-based first-line chemotherapy， higher NLR is associated with poor prognosis in the SCLC patients， and higher PLR is associated with poor prognosis in the LS-SCLC patients.