Objective: To study the relationship of serum neurotransmitters with anxiety depression, T lymphocyte subsets and NK cells in patients with lung cancer chemotherapy. Methods: 56 cases of patients with advanced lung cancer who received chemotherapy in the First Affiliated Hospital of Chengdu Medical College between July 2013 and August 2016 were collected as observation group, and 50 healthy subjects who received physical examination in our hospital during the same period were selected as normal control group. Serum neurotransmitter, negative emotions and immune index levels were compared between the two groups of subjects. Pearson test was used to evaluate the relationship of serum neurotransmitter contents with negative emotions and immune index levels in patients with lung cancer chemotherapy. Results: Serum neurotransmitters DA, 5-HT and NE contents in observation group were lower than those in normal control group; SAS and SDS scores were higher than those of normal control group; peripheral blood CD4+T lymphocyte level, CD4+/CD8+ ratio and NK cell level were lower than those in normal control group while CD8+ T lymphocyte level was higher than that in normal control group. Pearson test showed that serum neurotransmitters DA, 5-HT and NE contents in patients with lung cancer chemotherapy were directly correlated with anxiety depression, T lymphocyte subset and NK cell levels. Conclusion: Serum neurotransmitter expression decrease in patients with lung cancer chemotherapy, and this is one of the important causes of anxiety depression and immune dysfunction in patients.