Objective: Analyze the effects of combined treatment with budesonide and montelukast on T lymphocyte subsets and daytime and nighttime symptoms in children with bronchial asthma. Methods: All cases are from pediatric patients with bronchial asthma who were admitted and treated at Shangrao Maternal and Child Health Hospital between January 2022 and December 2024, with a total of 60 cases selected, and randomly divided into a control group and a treatment group, with 30 cases in each group. The control group was treated with aerosol inhalation of budesonide suspension, while the treatment group received combined treatment with Montelukast on the basis of the control group, The levels of peripheral blood T lymphocyte subsets, daytime and nighttime clinical symptom scores, and incidence of adverse reactions were compared between the two groups. Results: After treatment, both groups showed a significant decrease in CD3+^{, CD4}+ ^{and CD4}+^/CD8+^, and an increase in CD8⁺. Compared with the control group, the treatment group showed a decrease in CD3+^{, CD4}+ ^{and CD4}+^/CD8+^, and an increase in CD8+ (P<0.05). After treatment, the treatment group scoring lower than the control group (P<0.05). Adverse reactions in the two groups were comparable (P<0.05). Conclusion: Applying budesonide combined with montelukast in the treatment of children with bronchial asthma can effectively regulate the levels of T lymphocyte subsets, improve immune function, and alleviate clinical symptoms, with high safety.