There are few studies on the cause of death in patients with stage I non-small cell lung cancer after surgery. Our aim is to study the trend of cause of death and risk factors affecting prognosis in the patients. We retrospectively reviewed patients in Surveillance, Epidemiology and End results database from 2004 to 2015. The change trend between cause of death and follow-up time was studied by calculating the proportion of cause of death at different periods and analyzing the cumulative risk. COX risk regression model was performed by univariate and multivariate analyses for survival analysis. Finally, 23,652 patients were enrolled. In the whole cohort, lung cancer accounted for 18.68% of deaths, followed by other causes (9.57%), heart disease (5.12%) and COPD (3.89%). With the increasing of follow-up time, the cumulative incidence of lung cancer was always the highest, but the growth rate in the late follow-up period was slower than that caused by heart disease and COPD. The proportion of death due to lung cancer decreased from 53.1%-73.1% in 0-30 months after follow-up to 7.8%-41.4% in 90 months after follow-up, while the proportion of deaths due to heart disease and COPD increased. Age was an independent risk factor for lung cancer-, heart disease- and COPD-specific survival, while lobectomy resection was a protective factor, even in patients older than 70 years old. In conclusion, during the follow-up period, lung cancer was still the main cause of death, but the proportion of patients died of heart disease and COPD increased gradually, especially in elderly. Furthermore, age was an important independent factor affecting prognosis, particularly for heart disease- and COPD-related mortality. The application of wedge resection in elderly patients needs further exploration.