Abstract: Objective: To study the relationship between PET/CT imaging manifestations of the TNM-stages of lung cancer (LC) and the expression of VEGF protein in serum. Methods: Fifty-three LC patients, with PET/CT imaging performed before treatment, were enrolled in this study. The expression of serum VEGF protein was examined by quantitative sandwich enzyme-linked immunosorbent assay(ELISA R&D system). A comparison of the PET/CT manifestations of the T-stage and metastasis (lymph nodes and distance) of the lung carcinoma along with the serum VEGF expression was performed. Results: PET/CT imaging manifestations: for T-staging, there were 11 patients staged as T1, 9 as T2, 18 as T3, and 15 as T4. In 22 patients there was mediastinal node metastasis. There were 9 patients with distant metastasis. The expression level of serum VEGF in LC patients was 378.02±180.79 ng/l, significantly different from the level seen in normal patients(P<0.05). There was no significant difference in the level of serum VEGF between T1 and T2 stage cases, while the expression level of serum VEGF was significantly different between lowT-stages(T1, T2) and high T-stages(T3, T4). The expression level of serum VEGF protein of those with mediastinal node metastasis was 561.50±104.55 ng/l, significantly different from that of patients without metastasis (t=12.21, P<0.05). The expression level of serum VEGF of those with distant metastasis was 614.11±158.81 ng/l, significantly different from that of patients without distant metastasis (t=5.30, P<0.05). Conclusion: 1) The level of serum VEGF in LC patients was high. 2) There was a correlation between metastasis(lymph nodes and distance) and the expression level of serum VEGF. 3) With increased TNM-stage, the expression level of serum VEGF protein became higher.