Objective To study the imaging findings of gastrointestinal stromal tumor, and analyzes its malignant judgment. Methods Our hospital patients with gastrointestinal stromal tumor as the research object, 42 cases of patients were retrospectively analyzed the clinical data and imaging diagnosis information, and comparing the imaging findings and pathologic diagnosis of patients. Results 42 cases patients were confirmed by surgery and pathology of gastrointestinal stromal tumor, including gastric stromal tumor, small intestinal stromal tumor, colon stromal tumor and there were 14 cases of rectal stromal tumor, 18 cases, 6 cases and 4 cases; Tumor between 2.5 cm to 20 cm in diameter, the average diameter was (13.7±2.3) cm, tumor shape: round or class round 15 cases, 27 cases of irregular points leaf form. Benign and malignant gastrointestinal stromal tumor of gastrointestinal stromal tumor in 14 cases and 28 cases respectively. By CT examination, benign tumors in patients with tumors are under 5 cm in diameter, and the density of tumor even, not seen significant calcification. Malignant tumor patients in more than 5 cm in diameter, tumors had uneven density, and shape is irregular, bleeding from low density area in the center of the tumor, is no clear boundary between between edge and the surrounding tissue, the enhancement scanning visible edge has obvious strength phenomenon, but the center did not see. Some patients exist lymph node metastasis or spread to the lier, involving the mesentery. Conclusion Patients with gastrointestinal stromal tumor by CT examination, to tumor size, shape, edge, coated and reinforcement degree, growth mode and the degree of necrosis was more clear visual observation, and according to its main clinical manifestation to identification of benign and malignant tumor, especially tumor size and fission number is an important basis of judging malignant, clinical diagnosis, differential and treatment of patients is of great significance.