Objective To study the value of pre-surgery computed tomography(CT)scan on post-surgery pathological risk grades of gastrointestinal stromal tumor(GIST).Methods Forty-one patients of GIST were retrospectively evaluated and confirmed by histological diagnosis. Tumor size, density, margin, contour, location, growth pattern, degree and pattern of lesion enhancement was analyzed. Results Based on pathological results, the total diagnosis accuracy of location and character on CT is 95.1%(39/41)and 92.6%(38/41), respectively.Tumors size of low risk group was smaller than that in the other two groups(P>0.05).There was no significant difference in tumor size between moderate and high risk groups. Using Chi-test analysis, tumor density, margin, contour, growth pattern was statistically different among different pathological risk grades (P < 0.05). CT features of enhancement were not significantly different among the pathological risk groups (P > 0.05). Conclusions CT plays an important role not only in the detection and localizing GIST but also in the evaluation of the extension and characteristics of these tumors. CT imaging can predict the invasive behaviors through tumor density, size, shape, contour, growth pattern and enhanced pattern.