HCG is human chorionic gonadotropin, which is mainly secreted by placental tissue and released into the blood. Therefore, a high HCG is generally suggestive of pregnancy, and in rare cases it may be caused by trophoblastic disease. When HCG is elevated, an ultrasound examination and related symptoms can be performed to make a comprehensive judgment.1. Pregnancy: HCG values are normally lower than 5 U/L, and if a high HCG value occurs, it is generally suggestive of pregnancy. In case of intrauterine pregnancy, the HCG value will double every other day. In case of ectopic pregnancy, the HCG value will generally double poorly and the pregnancy needs to be terminated early after the diagnosis is confirmed by ultrasound examination; 2. Gestational trophoblastic disease: If the HCG value is high but there has been no recent intercourse, it may also be caused by diseases, such as gravida and choriocarcinoma. Gravidity may be manifested by vaginal grape-like blister tissue and abdominal pain. Clear hysterectomy is required, and total hysterectomy may be an option if necessary for those who are older or do not require fertility. Choriocarcinoma may have abnormal vaginal bleeding, irregular enlargement of the uterus and other manifestations, and chemotherapy is the main treatment. 3. Incomplete miscarriage: If a woman who has miscarried is found to have high HCG in the recheck, it may be caused by incomplete miscarriage, suggesting that there is still placental tissue remaining in the uterus, and may need to perform a curettage after diagnosis.