【】Objective: To explore the correlation between LncRNA MALAT1 and peripheral blood inflammatory composite indicators in lymph node metastasis of non-small cell lung cancer (NSCLC). Methods: A total of 120 NSCLC patients who were treated from March 2022 to February 2025 were selected as the research subjects. They were divided into a metastasis group (26 cases) and a non-metastasis group (94 cases) according to whether mediastinal lymph node metastasis occurred. The differences in LncRNA MALAT1 and peripheral blood inflammatory composite indicators between the two groups were compared. The efficacy of each indicator in diagnosing mediastinal lymph node metastasis of NSCLC was detected, and the correlation between LncRNA MALAT1 and peripheral blood inflammatory composite indicators was also detected. Results: The serum LncRNA MALAT1 in the metastasis group was 15.26±3.48, significantly higher than 11.68±2.67 in the non-metastasis group (P < 0.05). When comparing the preoperative peripheral blood inflammatory composite indicators between the two groups, the NLR in the metastasis group was 3.59±0.92, higher than 1.89±0.84 in the non-metastasis group; the LMR in the metastasis group was 4.11±1.83, lower than 7.34±2.39 in the non-metastasis group; the PLR in the metastasis group was 165.59±42.24, higher than 118.42±30.14 in the control group, and all the differences were statistically significant (P < 0.05). In the ROC curve, the AUC of LncRNA MALAT1 was 0.9124 (95%CI = 0.8593 - 0.9656), the AUC of NLR was 0.9358 (95%CI = 0.8905 - 0.9810), the AUC of LMR was 0.8601 (95%CI = 0.7801 - 0.9400), and the AUC of PLR was 0.8187 (95%CI = 0.7116 - 0.9258), all of which had good diagnostic efficacy for NSCLC lymph node metastasis. The results of correlation analysis showed that the serum LncRNA MALAT1 level in the metastasis group was positively correlated with the levels of NLR, LMR, and PLR, with correlation coefficients of r = 0.712, r = 0.628, and r = 0.587 respectively. Conclusion: LncRNA MALAT1 and peripheral blood inflammatory composite indicators have good diagnostic efficacy in predicting lymph node metastasis of NSCLC, and there is a positive correlation between LncRNA MALAT1 and peripheral blood inflammatory composite indicators.