Abstract：Objective：To observe the clinical effect of Huai'er Granules combined with neoadjuvant chemotherapy on non-small cell lung cancer （NSCLC） in senile and its effects on tumor markers and T lymphocyte subsets. Methods： A total of 80 cases of senile NSCLC patients treated at Lishui City People's Hospital from August 2021 to December 2023 were selected and divided into the control group and the study group according to the random number table method， with 40 cases in each group. The control group was treated with neoadjuvant chemotherapy， and the study group was additionally treated with Huai'er Granules in addition to the neoadjuvant chemotherapy. Both groups were treated for two cycles，with a treatment cycle lasting 21 days. After treatment，clinical effects were evaluated；the changes in serum tumor markers [carcinoembryonic antigen （CEA） and cytokeratin 19 fragment （CYFRA21-1）]， cognitive function， and T lymphocyte subsets were compared between the two groups. Results： After treatment， the objective response rate（ ORR） and disease control rate（ DCR） in the study group were 87.50%（ 35/40） and 95.00%（ 38/40） respectively， compared to 60.00% （24/40） and 80.00% （32/40） in the control group， with significant differences between the two groups（ P＜0.05）. After treatment，the levels of CEA and CYFRA21-1 in the two groups were reduced when compared with those before treatment （P＜0.05）， with the study group showing significantly lower levels than the control group （P＜0.05）. After treatment， the incidence of cognitive dysfunction was 7.50% （3/40） in the study group and 25.00% （10/40） in the control group， with a significant difference （P＜0.05）. After treatment， the levels of CD3+ ， CD4+，and CD4+/CD8+ in the two groups were decreased when compared with those before treatment （P＜0.05），and CD8+ levels were increased （P＜0.05）；but the study group had significantly higher levels of CD3+，CD4+，and CD4+/ CD8+ and lower level of CD8+ compared to the control group （P＜0.05）. During the treatment，there was no significant difference in the incidence of adverse reactions such as rash， nausea and vomiting， anemia， liver and kidney dysfunction， and diarrhea between the two groups （P＞0.05）. Conclusion： Huai'er Granules combined with neoadjuvant chemotherapy have a significant curative effect on senile NSCLC patients，which can improve cognitive and immune functions and reduce tumor marker levels，with good safety.