Objective：To explore the diagnostic value of zinc transporter 8 autoantibody (ZnT8A) and the relationship between ZnT8A and human leukocyte antigen (HLA)-A genotype in the patients with type l diabetes mellitus (T1DM) in Jiangsu Province. Methods：A cross-sectional and case-control study was carried out. The glutamic acid decarboxylase antibody (GADA)，protein tyrosine phosphatase-2 antibody (IA-2A)，insulin antibody (IAA)，and ZnT8A were detected by radioimmunity ligand assay and the HLA gene polymorphism of HLA-A was examined with PCR-SSO method in T1DM and healthy controls (HC). Results：①Among 140 T1DM cases，46.4% (65/140) had positive ZnT8A，while the positive rate in 102 healthy controls was 1.0% (1/102). The positive rate of ZnT8A was significantly higher in T1DM than that in HC (P＜0.05). ②On the base of testing GADA，IAA and IA-2A，the positive rate of at least one antibody was 70.7%(99/140) and it increasd to 86.4% (121/140) when ZnT8A was further tested (P＜0.05). ZnT8A in the other three antibody-negative patients still had a positive rate of 15.7%. ③HLA-A*24 in the T1DM group was significantly higher than that in the healthy control group (P＜0.05，OR=1.654)，while A*33 decreased significantly (P＜0.05，OR=0.161) compared with the healthy control group. ④HLA-A*02 was significantly higher in the ZnT8A-positive group than in the ZnT8A-negative group (P＜0.05，OR=0.318)，but no significant difference was found after adjusting for the effect of course of disease，age of onset，and BMI. Conclusion：The positive rate of antibody increase by 15.7% in T1DM patients when ZnT8A is further tested. ZnT8A can improve the diagnostic sensitivity. No relationship between HLA-A and ZnT8A was found.