Patients need to prepare for five aspects before the colonoscopy, which are dietary conditioning, bowel cleansing, calming the emotions, perfecting the examination, and anesthesia evaluation. 1. Diet regulation: do not eat too greasy food a few days before the examination to prevent constipation, do not eat spicy and stimulating food, it is recommended that the day before the examination into the fluid, non-dregs of food, such as eating thin rice and noodles. 2. Cleansing: Cleansing can enteroscopy results, so before the examination must pay attention to empty the intestines. Take laxatives such as magnesium sulfate, sodium phosphate, and mannitol 4 to 8 hours before the examination to promote emptying. 3. Emotional calm: colonoscopy will bring some discomfort to the patient, such as abdominal pain, abdominal distension, etc. It is recommended that the patient’s emotions before the examination to avoid excessive tension. 4. Perfect examination: cardiovascular and cerebrovascular patients need to do ECG, brain CT and blood routine examination before the operation, in order to avoid stimulating factors in the examination to induce related diseases. 5. Anesthesia evaluation: before painless colonoscopy, anesthesiologists need to do anesthesia evaluation on patients to ensure the smooth progress of the examination. A series of preparations are needed before the colonoscopy, which must be prepared according to the doctor’s instructions, otherwise the bowel preparation will be ineffective and affect the examination effect.