Objective: To investigate the affecting factors of type 1 diabetes mellitus(T1DM) in children, and to provide reference for the prevention and treatment measures in the future. Methods: A case-control study was carried out among 106 children diagnosed with T1DM in a hospital in Shenyang. At the same time, 106 healthy children were selected as the control group by 1∶1 matching of age, gender and living area. The early life-related factors that may affect the development of T1DM in two groups were investigated by questionnaire. Results: The average age of diagnosis in 106 cases with T1DM was(8.02±3.49) years, girls accounted for 60.4% and boys 39.6%. Multi-factor Logistic regression analysis showed that high family socioeconomic status and higher education of fathers were associated with lower odds of development of T1DM. Family member smoking(OR=2.51, 95%CI=1.19-5.29), family history of diabetes(OR=2.56, 95%CI=1.18-5.55), maternal obesity(OR=5.42, 95%CI=2.49-11.83) and infection during pregnancy(OR=3.45, 95%CI=1.04-11.46) were associated with higher risk of T1DM(P<0.05). Conclusion The occurrence of T1DM in children is affected by many factors including heredity, maternal health during pregnancy and family economy,highlighting the importance of early life prevention of T1DM.