The treatment of mental disorders during pregnancy is challenging. Modified electroconvulsive therapy (MECT) has become one of the important and powerful treatment methods, which is safe with a rapid onset of action and fewer side effects, benefiting for patients in acute stage especially for those with suicidal ideation. This article mainly discusses the superiority of MECT in the treatment of mental disorders in pregnancy, as well as the treatment principle in women and fetus. Through pretreatment evaluation and closely monitoring of therapeutic efficacy during and after treatment, the complications of pregnant women and fetuses, such as vaginal bleeding, premature labor and fetal arrhythmia, can be effectively minimized. Taken together, MECT seems to be a safe and effective measure in treating mental disorders during pregnancy.