ObjectiveTo study the influence of psychological intervention on the immune function and psychological state in patients undergoing chemotherapy after radical operation of colorectal cancer. MethodSixty-four patients who underwent chemotherapy after eradicative resection of rectal cancer between August 2008 and August 2013 were randomly divided into control group and intervention group. Both the two groups of patients accepted conventional chemotherapy and nursing, while patients in the intervention group were also given psychological intervention. At the beginning of and 8 weeks after the therapy, self-evaluation of anxiety scale and depression self-rating scale were used to determine the psychological state (anxiety and depression) of patients in the two groups, and we evaluated the effect of psychological intervention. At the same time, the immune index and inflammatory cytokines were determined and compared between the two groups. ResultsBefore treatment, patients in both the two groups were accompanied by mild anxiety and depression. After psychological intervention, compared with the control group, anxiety and depression of patients in the intervention group were significantly alleviated (P<0.05). Before chemotherapy, patients in the two groups were not statistically different in the immune factor index (P>0.05). After chemotherapy, compared with the control group, natural killer cells, CD3+, CD4+, CD4+/CD8+, C-reactive protein, immunoglobulin (Ig) G, interleukin (IL)-10 level of the intervention group significantly increased (P<0.05), and IL-6 and tumor necrosis factor alpha expression decreased (P<0.05). CD8+, IgA and IgM were not significantly changed (P>0.05). ConclusionsPsychological intervention can alleviate anxiety and depression and improve the immune function in patients who undergo chemotherapy after radical operation of colorectal cancer, which is an effective auxiliary treatment.