Objective:To identify the positive rate of islet autoantibodies in patients with type 1 diabetes (T1D) according to age and disease duration. Methods: We collected the general information and laboratory tests of 537 patients diagnosed with T1D,and measured the levels of islet autoantibodies. The subjects were subdivided into different groups according to their age and disease duration. Then we investigated the association of islet autoantibodies with age and disease duration. Results:Among 537 patients,the average age and disease duration was 32.84 ± 17.98 year-old and 4.31 years,respectively. 75.4% of patients were positive for at least one islet autoanbotidy(55.7% within 5 year of the disease onset:44.1% after 5 year,P=0.032). 54.4% of the patients were positive for glutamic acid decarboxylase antibody (GADA),30.8% for protein tyrosine phosphatase antibody (IA-2A),28.2% for zinc transporter 8 antibody(ZnT8A) and 23.5% for islet cell antibody (ICA). The positive rate was significantly higher in patient whose age was less than 12-year-old than in those over 12 (GADA 76.9% vs 57.4%,IA-2A 65.4% vs 31.7%,ZnT8A 38.5 % vs 24.1%,at least one islet autoanbotidy 83.3% vs 75.7%). Conclusion:The rates of positive islet autoantibodies significantly decreased along with the disease duration. Younger patients had higher rate of positive islet autoantibodies. Therefore,more attention should be paid when type 1 diabetes is diagenozed in adults.