The treatment of constipation is a worldwide problem. There are three types of constipation: slow-transit colonic, obstructive outlet, and mixed. The slow-transmission colon type is characterized by a lack of bowel movements, while the obstructive outlet type is characterized by a feeling of bowel movements but difficulty in passing them. Patients with chronic constipation are recommended to undergo the following tests to clarify the cause and type of constipation, so that treatment can be more targeted. Defecography is an examination method that combines dynamic and static observation of the rectal part of the anal canal when the patient “defecates” by injecting contrast into the patient’s rectum. It can show the functional and organic lesions of the anorectal area, and can be used to diagnose rectal prolapse, rectal prolapse, pelvic floor muscle spasm syndrome and other outlet obstruction type constipation. In addition, this test can also diagnose pediatric megacolon. Second, the colonic transmission test is performed by having the patient take a capsule (containing 20 small capsules of an opaque marker) orally. Radiographic examination is performed at the 24th, 48th and 72nd hours to determine the peristaltic function of the colon by observing different parts of the marker. The balloon force-out test is an auxiliary examination of rectal defecation function, and is important for determining the pelvic floor muscle, abnormal contraction of the external sphincter and decreased rectal sensory function. Measurement method: Insert the catheter into the balloon, tie the end of the balloon with a thread, lubricate the outside of the balloon with water, insert the balloon into the rectal jug abdomen, inject 50ml of water (or air), hold the catheter with a clip, ask the patient if he/she feels the urge to defecate during the process of water injection, and record the amount of water injected (rectal sensory threshold) when the urge to defecate first starts. The patient should take the squatting position and side lying position to do defecation to force out the balloon, and record the time of expulsion. 5 minutes to expel the balloon is a negative balloon force-out test, which is a normal outlet function; more than 5 minutes to expel or even not to expel is a positive balloon force-out test, which means the patient has outlet obstruction disease. Anorectal manometry can measure rectal resting pressure, anal canal resting pressure, anal canal systolic pressure, active systolic pressure, length of anal canal high-pressure area, rectal sensory threshold, rectal compliance, rectal-anal inhibition reflex and other indicators, which can be used for the diagnosis of constipation typing, and congenital megacolon, internal sphincter loss delay, puborectal muscle spasm syndrome, pelvic floor spasm syndrome and other diseases can be diagnosed from the above indicators.