Abstract: Objective To investigate the levels of serum interleukin-4(IL-4), interleukin-6(IL-6)and interleukin-8(IL-8)in patients with treatment-resistant schizophrenia(TRS). Methods A total of 112 male patients with TRS, 117 male patients with non-TRS chronic schizophrenia and 113 healthy controls were enrolled. The mental symptoms of the patients were evaluated by Positive and Negative Syndrome Scale(PANSS). Enzyme-linked immunosorbent assay(ELISA)method was used to detect serum IL-4, IL-6 and IL-8 levels. Results The levels of IL-6 and IL-8 in the TRS group and schizophrenia group were significantly higher than those in the control group(P<0.05), but there was no significant difference in IL-8 between the TRS group and the schizophrenia group(P>0.05). There was no significant difference in IL-4 level among three groups(P>0.05). The area under curve(AUC)of receiver operating characteristic curve(ROC)was 0.823 for TRS group and control group. Conclusion There are obvious immune abnormalities in TRS patients, and IL-6 may be important biological indicators of TRS.