Imaging methods for gastrointestinal diseases were based on X-ray imaging until the 1970s, but the development of fiberoptic endoscopy in the 1980s has replaced X-ray imaging. Endoscopy can directly observe the location, size, scope, and color of lesions and obtain pathological results through biopsy, while ligation and other treatments can be performed on polyps and other lesions. Studies have shown that multilayer spiral computed tomography (CT) examination after standardized gastrointestinal preparation and full use of the advantages of various 3D postprocessing reconstruction techniques are of great clinical value in the detection of gastrointestinal diseases, determination of the nature of lesions, localization of lesions, and staging of gastrointestinal malignancies and can make up for the shortcomings of fiberoptic endoscopy, and various 3D postprocessing reconstruction modes have their own advantages and disadvantages. Among them, conventional CT cross-sectional images are the basic images for the diagnosis of various gastric testicular lesions. Axial images, especially thin-layer axial images, can detect the absolute majority of lesions, but there are limitations in observing the anatomical position of lesions, invasion of surrounding tissues, lymph node metastasis, vascularity, and determination of the stage of malignant tumors.