Abstract： Objective： To observe the effect of modified Ganmai Dazao tang combined with routine western medicine therapy on the immune state， mental state and quality of life in patients with depression caused by malignant tumor. Methods： A total of 92 cases of patients with depression caused by malignant tumor were selected and divided into the observation group and the control group according to the random number table method，46 cases in each group. The control group was given routine symptomatic treatment，and the observation group was additionally given the oral administration of modified Ganmai Dazao tang based on the treatment of the control group. Before and after treatment， the immune state， mental state and quality of life in the two groups were compared. Results： Before treatment， there was no significant difference being found in the comparison of the levels of immunoglobulin including IgA，IgG and IgM，T cell subsets including CD3 +，CD4 +，CD8 + and CD4 +/CD8 + as well as NK cells in serum between the two groups(P＞0.05). After treatment，the levels of IgA，IgG and IgM in the control group were decreased when compared with those before treatment(P＜0.05)；the levels of IgA，IgG and IgM in the observation group were increased when compared with those before treatment，and the above levels were higher than those in the control group(P＜0.05). After treatment，CD3 + and CD4 + in the control group were decreased when compared with those before treatment， and CD8 + was increased(P＜0.05)； CD4 + and CD8 + in the observation group were decreased when compared with those before treatment；CD4+ in the observation group was higher than that in the control group，and CD8 + was lower，differences being significant(P＜0.05). After treatment，the absolute count of NK cells in the control group were decreased when compared with that before treatment，and the absolute count of NK cells in the observation group was increased，and it was higher than that in the control group(P＜0.05). Before treatment， there was no significant difference being found in the comparison of the scores of European Organization for Research and Treatment of Cancer Quality of Life Questionnaire(EORTCQLQ-C30) between the two groups(P＞0.05). After treatment，the scores of physical function and emotional function in the observation group were higher than those before treatment and those in the control group；the symptoms scores of fatigue，nausea，vomiting and pain as well as shortness of breath and insomnia were lower than those before treatment and those in the control group，and the overall health score was higher than that before treatment and that in the control group，differences being significant(P＜0.05). Before treatment，there was no significant difference being found in the comparison of the scores of Self- rating Depression Scale(SDS) and Hamilton Depression Scale(HAMD) between the two groups(P＞0.05). After treatment， the scores of SDS and HAMD in the control group were increased when compared with those before treatment(P＜0.05)； the scores of SDS and HAMD in the observation group were decreased when compared with those before treatment， and the above scores in the observation group were lower than those in the control group(P＜0.05). Conclusion：Modified Ganmai Dazao tang combined with routine western medicine therapy for depression caused by malignant tumor can significantly improve the immune function and mental state of patients，and enhance their quality of life at the same time.