Objective To investigate the value of CT grading diagnosis in clinical therapy of acute pancreatitis. Methods CT scanning was carried out in patients with acute pancreatitis between 2003 and 2009, and Enhancement CT scanning was carried out in patients without contraindications of contrast medium. Two radiologists analyzed the images and made CT grading diagnose. Contrast study was made between CT grading diagnose and clinical scale as well as prognosis. Results In 518 cases, the CT grading was as the following: grade A 9 cases, grade B 66 cases, grade C 105 cases, grade D 147 cases, and grade E 191 cases. Patients with grade A and B were fully recovered after conservation and supportive treatment. In cases of grade C, only 2 patients had recurred pancreatitis after conservation treatment, and others were fully healing. Ninety-four patients who needed operation and 23 patients who died were all occurred in grade D and E. Conclusion CT grading diagnosis of acute pancreatitis can reflect the range, extent, and course of disease, and it has good dependablity with clinical grading.