Abstract: Autoimmune type 1 diabetes mellitus is one of the common complications during pregnancy, which can lead to increased maternal and fetal complications.This paper presents the screening and diagnostic standards for pregnant women with autoimmune type 1 diabetes mellitus, and proposes that adequate preparation before pregnancy, intensive monitoring during pregnancy and excellent glycaemic control throughout the pregnancy by diet control and insuline injection can reduce maternal and fetal complications , which improves the outcome of pregnancy.