Abstract: Objective: To evaluate CT function in diagnosis die diseases of digestive tract,to discuss its far-reaching significance in guiding therapy and judging prognosis .Methods:Adopt special intestinal preparing methods and use improved scanning technique, mutual contrast with the result of gastrointestinal meal perspective and its endoscopic examination, study carefully on 32 cases, all results were confirmed by clinical and pathology. Result: According Dukes' improvement divide for method ,all tumor patients were in the second phase or above. There were 4 cases being misdiagnosis, the accuracy of qualification diagnosis is 87.5 percent, the relevance ratio of all niduses is 100 percent Conclude : CT is advanced scientist method,these CT features correlates well with the surgical finding and pathology .Because CT has so many advantages. for example: easily. quickly, painlessly, very clearly and accuracy. it will be used widely in the diseases of digestive.