In the eighth TNM staging system proposal for NSCLC recently, classification of N stage is based on anatomical position of positive lymph nodes. We aimed to expand the sample volume to identify the value of positive lymph node number or ratio in prognosis and predictive effect for postoperative radiation. Clinicopathological characters of 109026 NSCLC patients were collected from the SEER Database. Kaplan-Meier curves and cox regression methods were used for survival analysis. Compared with positive lymph node number equal to 0, 1-3 and >3 groups were independent prognostic factors (1-3: HR 2.856, p < 0.001; >3: HR 3.358, p < 0.001), so as the 0-50% and >50% positive lymph node ratio groups (0-50%: HR 2.124, p < 0.001; >50%: HR 3.358, p < 0.001). And in the groups of N2&positive lymph node number ≥4 and N2&positive lymph node ratio >50%, postoperative radiation related to positive prognosis of NSCLC patients. In conclusion, positive lymph node number or ratio was associated with survival as an independent indicator in NSCLC. They also had predictive effects for postoperative radiation, while N nodal stage not.