The left abdominal pain parallel to the navel may be caused by irritable bowel syndrome, ulcerative colitis and colon cancer. 1. Irritable bowel syndrome: it is a kind of functional bowel disease, its main manifestation is abdominal pain or abdominal discomfort, the location is not certain, the lower abdomen and left lower abdomen is common, can be accompanied by diarrhea or constipation, abdominal distension and other symptoms, which can be manifested in the left abdominal pain parallel to the navel and pain when pressed. 2. Ulcerative colitis: it is a kind of inflammatory bowel disease, which mainly manifests as recurrent abdominal pain, mostly mild to moderate hidden pain in the left lower abdomen, obvious when pressing, and also manifests as diarrhea, mucus-pus-blood stool, fever, nausea, loss of appetite, weight loss and other symptoms, which also manifests as left abdominal pain parallel to the navel and pain when pressing. 3. Colon cancer: it is a malignant tumor occurring in the colon area, with no obvious symptoms in the early stage, with the progress of the disease, it can appear the change of stool habit and character, abdominal pain, abdominal mass, anemia, fatigue, emaciation, intestinal obstruction and other symptoms, which can also be manifested as the left abdominal pain parallel to the navel, pressing pain. There are many other causes of left abdominal pain parallel to the belly button, should be taken seriously, timely consultation, identify the cause of the disease, and follow the doctor’s advice for further treatment or treatment.