Abstract: Objective To investigate the clinical efficacy and prognostic significance of ribonucleotide reductase M1(RRM1) expression in lung tissue of patients with Non-small cell lung cancer(NSCLC) treated with gemcitabine combined with platinum. Methods Tumor samples obtained from 60 patients with advanced NSCLC were collected to investigate the expression level of RRM1 by the immunohistochemical methods.Relationships between the expression and clinical characters,efficacy,overall survival time of patients with advanced NSCLC were analyzed. Results The RRM1 expression was significant difference between male and female（P＜0.05),while there was no correlation between RRM1 expression and age,pathological type and TNM stage（P＞0.05）.Patients with low expression had remarkably higher response rate (57.7%) and disease control rate(69.2%) to gemcitabine than overexpression RRM1 group（29.4%,35.3%）（P＜0.05).Low expression group of RRM1 had longer overall survival(18 months，13 months),longer progression free survival (6months,4months) and higher 1-year survival rate(69.2%,58.8%),2-year survival rate((23.1%,3%) than over expression group（P＜0.05). Conclusion The patients with low RRM1 expression levels have higher response to chemotherapy and longer survival time.RRM1 expression is an independent prognostic factor.The result of this study may be helpful for selecting patients of advanced NSCLC with low RRM1 expression levels to accept gemcitabine combined with platinum.