Objective To investigate the clinical significance of TMB for patients with NSCLC who received platinum⁃based adjuvant chemotherapy. Methods A total of 78 patients with non⁃squamous NSCLC who received platinum⁃based adjuvant chemotherapy were included in this study. Somatic mutation detection and TMB analysis were performed using next⁃generation sequencing. The data on recurrence and long⁃term survival in the patients was obtained by telephone follow⁃up. Survival analysis between TMB and prognosis was performed and then adjusted by multivariate Cox regression. Results The most common somatic mutation genes were TP53，EGFR， LRP1B，DNMT3A and FAT3 in the 78 patients. The patients were assigned to TMB ⁃ L group or TMB ⁃ H group based on the median TMB threshold. Association analysis indicated that patients with TMB ⁃H had a poorer OS. Besides，multivariate Cox analysis suggested that TMB was an independent factor for OS. Conclusions Higher TMB status had an adverse impact on OS in the patients with non⁃squamous NSCLC who received platinum⁃based adjuvant chemotherapy. And these research findings should be further verified by prospective studies.