The aim of the study is to observe the effect of gefitinib on the quality of life, the level of inflammatory factors, T cell subsets and serum tumor markers in elderly patients with Non-Small Cell Lung Cancer (NSCLC), and to explore its clinical value. 140 elderly patients with NSCLC admitted from Feb 2014-2016 were selected for prospective controlled analysis. According to the random number table method, the patients were divided into observation group, control group with 70 cases in each. All the patients were treated with routine supportive care. Patients in observation group were treated with gefitinib. Patients in control group received the GP regimen (gemcitabine+cisplatin). The changes of quality of life, inflammatory factors, T cell subsets, changes of serum tumor markers, the occurrence of adverse events and survival were compared between the two groups before and after treatment. The application value of gefitinib in the treatment of senile NSCLC was analyzed. The total effective rate was 47.14% in the observation group, which was higher than that in the control group (30.00%), the difference was statistically significant (P<0.05). The incidence of thrombocytopenia, anemia, granulocytopenia, nausea and vomiting in the observation group was lower than that in the control group. The incidence of diarrhoea and rash was higher than that of the control group (P<0.05). The quality of life of the two groups was improved compared with that before treatment, and the improvement of the observation group was more obvious (P<0.05). The levels of IL-2, IL-12 and IFN-γ in the two groups were significantly higher than those before treatment (P<0.05). The levels of CD4+, CD4+/CD8+ in the observation group significantly increased. CD3+ and VEGF decreased (P<0.05) after 2 courses. While no significant change was observed in the control group (P>0.05). In conclusion, gefitinib is safe and effective in the treatment of elderly patients with NSCLC, and can significantly improve their quality of life, inhibit the inflammatory response, improve immune function, downregulate VEGF expression. It is expected to extend the survival of patients or win opportunities for radical surgery, which is worthy of further attention.