1.If you need to examine the liver, gallbladder, bile duct, spleen, pancreas, renal artery, renal vein, retroperitoneal and peritoneal cavity lesions, and large abdominal vessels, you need to fast for more than 8 hours. 2.If you need to examine both kidneys, both ureters, bladder and prostate, you need to drink a moderate amount of water, about 500-1000ml, 1~2 hours before the examination, and please hold urine moderately before the examination, but you do not need to fast. 3.If you need to check the above two items at the same time, please fast for more than 8 hours and drink about 500-1000ml of water, but do not drink milk, soft drinks and other liquids, and hold urine moderately. 4.If you need to undergo transabdominal gastrointestinal ultrasound examination, it is recommended to eat a diet with less residue three days before the examination, and fast for more than 8 hours before the examination, but you can drink a moderate amount of water. 5.If you need transrectal ultrasound examination, you should fast for more than 8 hours before the examination and have a cleansing enema, but you can drink a moderate amount of water. 6.If you need to examine thyroid, parotid gland, breast, external genitalia, body surface, joints, nerves, etc., no special preparation is needed.