Objective To explore the application value of conventional multi-slice spiral CT scanning and post-processing technology in pulmonary sequestration. Methods A total of 21 patients with pulmonary sequestration admitted in our hospital from May 2015 to December 2017 were selected, and the clinical data and imaging data were collected, analyze and summarize the image manifestations of CT non-enhanced scan and the postprocessing techniques. Results Multi-slice CT non-enhanced scan showed that 21 cases located in the posterior basal segment of the lower lung. Type of disease: 13 cases of intrapulmonary sequestration, 8 cases of leaf pattern pulmonary sequestration. There were 4 cases of cystic lesions in CT plain scan, all of which were multilocular, the cysts contain liquid components, and the thickness of the cysts was not uniform. There were 4 cases of solid lesions, with obvious enhancement and clear edge. There were 13 cases of cystic solid mixed mass, and there were multiple cystic areas with gas in the lesions, with no obvious enhancement. The adjacent vessels of 1 lesions were thickened. According to the axial position of MIP and VR images, a total of 22 blood supply arteries and drainage veins from the systemic circulation were found in 21 patients. The overall appearance of blood supply arteries and venous drainage vessels was dynamically tracked. Nineteen cases were supplied by thoracic aorta and drained into pulmonary vein system, two by the upper segment of the abdominal aorta, and one by the peritoneal trunk. Conclusion Conventional multislice spiral CT scanning and post-processing technology can clearly display the appearance and vascular distribution of pulmonary sequestration, which provide reliable imaging evidence for the clinical operation plan.