Hardness around the belly button may be physiological factors, may also be pathologic factors, such as peritonitis, dyspepsia, acute enteritis and so on. 1. Physiological factors: often exercise, abdominal muscles are more developed, will lead to abdominal hardness around the navel, is a normal phenomenon, there is no other clinical manifestations, do not need to worry too much. 2. Peritonitis: usually associated with infectious factors, will make the belly button around the hard symptoms, may also be accompanied by nausea, vomiting, abdominal distension, abdominal pressure and pain and other symptoms. 3. Dyspepsia: Eating a lot of cold food or having a cold abdomen can cause dyspepsia, which can lead to hardness around the navel, accompanied by abdominal distension, abdominal pain, nausea and vomiting and other symptoms. 4. Acute enteritis: may be related to bacterial, viral or parasitic infections, can lead to hardness around the navel, accompanied by diarrhea, abdominal pain, abdominal distension, fever and other symptoms. Hardness around the navel, but also seen in other causes, discomfort, should seek medical attention in a timely manner, under the guidance of a professional doctor standardized treatment, so as not to delay the condition.