Objective Exploring the predictive value of prognostic nutritional index PNI and nutritional risk screening 2002 NRS2002 in predicting the prognosis of lung cancer patients using Cox proportional hazards model analysis. Method According to the inclusion and exclusion criteria a retrospective analysis was conducted on the clinical data of 652 lung cancer patients admitted to Shanghai Pulmonary Hospital from June 2021 to June 2023. Patients were followed up for 14 months after surgery and divided into two groups based on their prognosis Survival group n = 587 and death group n = 65 . The basic situation of the two groups was compared and a single factor was used to preliminarily select candidate factors. Cox proportional hazards analysis was conducted on variables with statistical differences to establish a prediction model. Receiver operating characteristic ROC curves were drawn to test the effectiveness of the prediction model. Meanwhile it is necessary to use the Kaplan Meier survival model to analyze the relationship between different PNI and NRS 2002 scores and survival. Result After 14 months of follow-up 587 patients with 652 lung cancer patients had no progression and 65 patients died or relapsed. Compared with the survival group the death group had a higher age of 66-70 years a history of alcohol consumption TNM stage Ⅲ PNI <45 and a higher NRS 2002 score of ≥3 before treatment which was statistically significant P<0. 05 . According to Cox proportional hazards analysis TNM staging PNI<45、A NRS 2002 score of≥3 before treatment is a prognostic factor for lung cancer patients P<0. 05 . Based on these factors a prediction model was established and validated using Bootstrap method. The ROC curve area was 0. 745 and the 95%CI was 0. 680-0. 810. This model can effectively predict the prognosis of patients. Meanwhile Kaplan Meier survival analysis showed that patients with PNI≥45 had longer survival times and lower mortality rates than those with PNI <45 The survival time of patients with NRS 2002<3 points is longer than that of patients with NRS 2002 ≥3 points and the mortality rate is lower than that of patients with NRS 2002≥3 points with statistical significance P<0. 05 . Conclusion The prognosis of lung cancer patients is influenced by TNM staging NRS 2002 score and PNI score. By constructing a predictive model it is possible to timely understand the preoperative nutritional status of patients identify high-risk states and carry out targeted interventions to improve prognosis.