〔Abstract〕 Objective To investigate the short-term and long-term effects of different radiotherapy doses in patients with advanced lung cancer. Methods A total of 81 patients with advanced lung cancer admitted to Henan Provincial Armed Police Corps Hospital from September 2018 to January 2021 were selected and divided into a control group with 40 cases and an observation group, with 41 cases according to the random number table method. The control group was given high-dose radiotherapy, the observation group was given low_x0002_dose radiotherapy, and the short-term and long-term efficacy, tumor markers, immune function and the occurrence of adverse reactions were observed in the two groups. Results The total effective rate was 78.05% in the observation group and 70.00% in the control group, and there was no significant difference between the two groups (P > 0.05). There was no significant difference in recurrence rate and mortality between the two groups (P > 0.05). The levels of carbohydrate antigen 125 (CA125), carcinoembryonic antigen (CEA) and cytokeratin 19 fragment antigen 21-1 (CYFRA21-1) in the two groups after radiotherapy were lower than those before radiotherapy, and there was no statistical significance between the two groups (P > 0.05). The levels of CD4+ and CD3+ in the two groups after radiotherapy were lower than before treatment, while the levels of the observation group were higher than those of the control group, and the level of CD8+ was higher than before treatment, while the level of CD8+ of the observation group was lower than the that of the control group, the differences were statistically significant (P < 0.05). The incidence of adverse reactions in the observation group was 7.32%, lower than 25.00% in the control group, and the difference was statistically significant (P < 0.05). Conclusion The application of low-dose radiotherapy to patients with advanced lung cancer can reduce the content of tumor markers, improve immune function, and reduce the incidence of adverse reactions, and the short-term and long-term efficacy of low-dose radiotherapy is comparable to that of high-dose radiotherapy