Currently, embryo transfer is performed under abdominal ultrasound guidance in many reproductive medicine centers in China and abroad. The advantages of abdominal ultrasound-guided embryo transfer are: the outer tube of the embryo transfer tube enters the endometrium clearly and easily; then, the inner tube enters the uterine cavity in a clear and precise position. In particular, it is more advantageous for those difficult transfers where the cervical canal – endocervix has been damaged or the canal is deformed. Only with proper urine volume, the abdominal ultrasound can visualize the condition of the cervical canal and uterine cavity of the uterus, which facilitates the embryo transferee to smoothly enter the embryo transfer tube into the uterine cavity.