Objective: To investigate the role of multilayer spiral CT (MSCT) in evaluating patients with gastrointestinal stromal tumors (GIST), particularly its utility in determining tumor size, immunohistochemical classification, and pathological risk. Methods: A retrospective analysis was conducted on 22 GIST patients, confirmed by surgical pathology between January 2019 and December 2023. All patients underwent MSCT examination prior to surgery. Tumor size, density, and immunohistochemical classification from the MSCT results were compared with the postoperative pathological findings. Additionally, the ability of MSCT to predict GIST risk grade was evaluated in combination with immunohistochemical analysis results. Results: No significant differences were found between the preoperative MSCT findings and postoperative pathological results in terms of tumor size, density, or immunohistochemical classification in GIST patients. MSCT also enhanced the ability to predict GIST risk grades. Conclusion: MSCT demonstrates significant clinical value in the diagnosis and risk assessment of GIST, aiding in the prediction of the tumor’s biological behavior and patients’ treatment responses.