The IUD is also known as the intrauterine device. The IUD is a contraceptive device that is placed inside the uterine cavity to achieve contraceptive effect through local tissue reaction to it. Because of its local action, it is a safe, effective, simple, economical and reversible method of contraception, and is one of the most commonly used contraceptive methods in clinical practice. There are many types of IUDs, mainly divided into inert IUDs and active IUDs. Currently, inert IUDs are no longer used and active IUDs are mainly used. Active IUDs contain copper, hormones, drugs, or active substances such as magnetism, and are more effective and have fewer adverse effects than first-generation IUDs. There are many different types of active IUDs and clinically the doctor will choose the relevant IUD to be placed according to the specific situation of each person’s uterus and clinical symptoms.