Objective To analyze the typical imaging features of spiral CT three phase dynamic enhancement of left lung upper lobe lung cancer. Methods Select 43 cases of left upper lobe lung cancer diagnosed by our hospital in July 2015 September 2016, patients underwent CT scan and three stage dynamic enhanced scan, and the imaging data and clinical data were collected, to analyze the image features of left lung upper lobe lung cancer in CT scan and three phase dynamic enhanced scan, and to diagnose the disease, and compare it with the operation and pathological findings. Results The 43 patients with left upper lobe lung cancer, 6 were mildly enhanced, 17 moderately enhanced, 7 highly enhanced, 4 markedly enhanced, and 9 non enhanced. In the 7 cases, the blood vessel shadow was seen in the early stage of the tumor, which showed irregular stripes, and the branches were visible. All the 7 cases were highly enhanced and were highly intensified. In 43 patients, there were 48 lesions, 38 solitary lesions and 5 multiple lesions. The detection rate of CT scan was 95.83% (46/48). 43 cases of CT image features analysis showed irregular shape in 4 cases, density and reinforcement uneven 6 cases, obstructive change in 7 cases, lymph node enlargement or fusion in 8 cases, there were 6 cases of pericardial effusion, 9 cases of lung cancer metastasis. Conclusion The intensification of lung cancer is mostly moderate and highly intensified. The three phase dynamic enhanced CT has a high detection rate of lung cancer in the upper left lung, which can display the typical imaging features of lung cancer.