Objective To study the serum expression of interleukin-36α(IL-36α),C1q/tumor necrosis factor-related protein 6(CTRP6)levels in patients with polycystic ovary syndrome(PCOS)and their diagnostic value.Methods A total of 98 PCOS patients diagnosed and treated in the Fifth Affiliated Hospital of Xinjiang Medical University from April 2019 to April 2022 were taken as the PCOS group,and 70 healthy women were taken as the control group.Enzyme-linked immunosorbent assay was applied to detect serum IL-36 α and CTRP6 level expression.The correlation between the expression of serum IL-36 α,CTRP6 levels and clinical indicators was analyzed by Pearson correlation analysis.Multivariate logistic regression analysis was used to analyze factors affecting the occurrence of PCOS.Receiver operating characteristic curve was used to evaluate the diagnostic efficacy of serum IL-36α,CTRP6 and combination in PCOS.Results Serum CTRP6(18.25±3.67μg/L),FPG(5.71±0.49nmol/L),FINS(18.96±2.68mIU/L),HOMA-IR(4.72±0.46),LH(6.17±1.44IU/L),T(1.32±0.42nmol/L),ovarian number(17.86±5.20)and ovarian volume(9.29±2.14cm3)in the PCOS group were higher,while serum IL-36 α(0.67±0.13ng/L)and FSH((4.27±1.33IU/L)were lower compared with those in the control group(5.14±1.28μg/L,4.76±0.54mmol/L,8.63±1.65mIU/L,1.83±0.33,4.92±1.39IU/L,0.86±0.28nmol/L,6.76±1.94 个,5.26±1.31cm3,2.11±0.38ng/L,5.42±1.67IU/L),with significant differences(t/x2=4.962～44.934,all P<0.05).Serum IL-36α(0.87±0.15ng/L,0.70±0.12ng/L,0.51±0.11ng/L,0.42±0.10ng/L)levels in patients with type 1,type 2,type 3,and type 4 PCOS were decreased sequentially,while CTRP6(14.07±3.35 μg/L,17.66±3.97 μg/L,21.16±3.67 μg/L,24.08±3.53 μg/L)were increased sequentially,with significant differences(F=61.281,33.854,all P<0.05).There was a negative correlation between serum IL-36 α and ovarian number,ovarian volume,FINS and HOMA-IR(r=-0.661,-0.621,-0.554,-0.671,all P<0.05).Serum CTRP6 was positively correlated with ovarian number,ovarian volume,FINS and HOMA-IR(r=0.625,0.631,0.537,0.738,all P<0.05).CTRP6(OR=1.327,95%CI:1.104～1.596)was an independent risk factor affecting the occurrence of PCOS,while IL-36 α(OR=0.707,95%CI:0.547～0.914)was a protective factor.The area under the curve(95%CI)of combination of IL-36 α and CTRP6 for the diagnosis of PCOS was 0.933(0.872～0.969),which was greater than that of IL-36 α,CTRP6 alone[0.870(0.821～0.926),0.898(0.854～0.940)],with significant differences(Z=4.258,4.119,all P<0.05).Conclusion The decrease of serum IL-36α and the increase of CTRP6 in PCOS patients are related to the severity of PCOS,and the combined detection of the two may have high diagnostic value for PCOS.