Based on the size of the gestational sac alone, it is not possible to determine whether the gestational sac is empty or not, and it is often necessary to combine the results of the ultrasound, progesterone, HCG values and so on to make a judgment. Generally speaking, if the gestational sac is 2-3cm in size, the ultrasound does not show any yolk sac, fetal heart or buds, and the progesterone and HCG values have decreased, then the gestational sac is empty. Empty sac is mostly due to poor development of the embryo, difficult to continue to develop, and there is no yolk sac, fetal buds and primitive vascular pulsation, etc., and spontaneous abortion or inevitable abortion or induced abortion often occurs. The common cause of empty sac is chromosomal abnormality of the embryo, which may be related to maternal immune status, intrauterine environment, sperm quality, egg quality, etc. If empty sac is diagnosed, it is often recommended to terminate the pregnancy in time, and the embryo can be removed from the uterine cavity by hysterectomy. After the surgery, it is necessary to pay attention to cleanliness and hygiene to avoid infection, prohibit sexual intercourse, and pay attention to rest and keep warm in daily life. It is recommended to do all the tests such as rheumatology and immunity indexes, ultrasound, etc. before the next pregnancy, and both parties should have a good life style.