1. Fasting examination: transabdominal organs (including liver, bile, pancreas, spleen, retroperitoneal organs, abdominal aorta, inferior vena cava, superior mesenteric artery, renal arteries and veins) require more than 8-10 hours of fasting. In addition, it is best to abstain from smoking before the examination on the same day. Except for special circumstances, patients are generally not recommended to have an examination in the afternoon. 2 . Retained urine examination: lower abdominal organs (including bladder, female uterine adnexa, pelvis, male prostate) need to drink about 1000ml-1500ml of water 1 hour in advance, to fully fill the bladder after examination to avoid intestinal gas interference. Zou Wen, Department of Ultrasound, The Third Affiliated Hospital of Nanchang University 3. For patients who need appendiceal examination, it is recommended that the patient be examined after emptying the bladder. 4. For patients who have difficulty in holding urine and elderly patients undergoing examination of uterine adnexa or prostate, intracavitary ultrasonography is recommended. 5. For patients requiring abdominal mass exploration, examination after enema evacuation is recommended.