Objective To investigate the imaging characteristics of high-risk patients with lung cancer screened and diagnosed by multi-slice spiral CT. Methods 107 subjects screened as high- risk group of lung cancer when receiving physical examination were selected as the research objects and were screened by multi-slice spiral CT. Patients whose screening results showed suspected lung cancer were given pathological examination and the results were recorded in detail. The accordance rate of multi-slice spiral CT in the screening and diagnosis of lung cancer was analyzed; The imaging characteristics of multi-slice spiral CT of patients with and without lung cancer were summarized and reorganized. Results ①Among the 107 high-risk patients with lung cancer, 78 cases were with suspected lung cancer screened by multi-slice spiral CT. 60 suspected cancer nodules and 20 suspected masses were found, a total of 80. Among the 78 patients with suspected lung cancer screened by multi-slice spiral CT, 64 patients were confirmed with lung cancer by pathological examination. The coincidence rate of multi-slice spiral CT in screening and diagnosis of lung cancer was 82.1% (64/78), including 55 (83.3%) cancer nodules, 11 (16.7%) cancer masses, a total of 66. ②There were 53 cases (82.8%) of lung neoplastci foci as nodules and 55 cancer nodules detected. The average size of the nodules was 1.8cm, including 33 (60.0%) complicated with obvious CT signs and the remaining 22 (40.0%) not. The pulmonary lesions were masses in 11 cases (17.2%) and 11 cancer masses were detected. The average size of nodules was 3.5cm, including 7 (63.6%) complicated with obvious CT signs and the remaining 4 (36.4%) not. Conclusion The proportion of cancerous nodes is higher than that of tumor masses in patients diagnosed with lung cancer. The imaging findings of multi-slice spiral CT are obvious.