The painfulness of a painful colonoscopy varies from person to person. Patients who have not had abdominal surgery and have a relatively standard body type should generally be able to tolerate the pain of a colonoscopy. On a scale of 0-10, it is usually around 2. If the abdomen has been operated, especially if the stomach or bladder or prostate has been operated, it may lead to abdominal intestinal adhesions, plus if the abdomen is relatively bulky and obese, the alignment of the intestine is more tortuous, and it should be more painful to do colonoscopy. If a pain scale from 0 to 10 is used, it is possible to reach a score of 10. In some patients, if the adhesions are heavy, it is difficult to reach a state of tolerance, that is, it is difficult to go to the location of the ileocecal region and terminate the colonoscopy. In conclusion, colonoscopy varies from person to person, because each patient’s intestinal alignment is different, and the colonoscopy also depends on the patient’s specific intestinal alignment, which is also related to the state of the patient’s intestinal preparation during the examination, and the presence or absence of fecal residue. For the operator, if the operator is less experienced, some difficulties may occur during the examination.