Objective The aim of this study was to investigate the association between maternal serum lev-el of neutrophil-lymphocyte ratio(NLR)and preterm labor in late stage of pregnancy. Methods In this retrospec-tive analysis of 200 pregnant women who underwent routine prenatal examination and delivered from January 12016 to December 312016 in the Maternal and Child Health family planning services,Xinhui District,Jiangmen city. The patients were divided into the PIR group(n = 100)and the control group(n = 100). The levels of leuko-cytes,neutrophils,lymphocytes,CRP and NLR of the two groups were compared. Multivariate analysis was per-formed to identify independent risk factor. Logistic regression model was established and the area under the receiver operating characteristic curve(ROC)was recorded for analysis of the prognostic value of different serum inflamma-tory makers in late stage of pregnancy. Results The NLR predict premature occurrence of AUC,the sensitivity and specificity of which were higher than those of peripheral blood leukocyte,neutrophil count,lymphocyte count and CRP. Conclusion Increased NLR in late stage of pregnancy could serve as an effective factor to predict the risk of preterm labor.