Canine gastrointestinal phymatosis at early stage was likely to be misdiagnosed as a common gastrointestinal disease as it seldom occurred，which could delay any effective treatment even aggravate the disease. A case of canine caecal phymatosis was introduced in the paper. An abdominal mass was primarily found in the affected dog，which was a mass at the end of the cecum as surgically detected，and confirmed as a gastrointestinal stromal tumor by histopathological examination. After surgical resection and other operations，the dog recovered. In addition，the characteristics of the disease，blood examination，imaging，cytology，histopathology and other diagnostic procedures and surgical treatment methods were discussed，with a view to providing a reference for clinical diagnosis and treatment of such disease.