Abstract: In order to evaluate the importance of ¹⁸F-FDG PET/CT imaging in diagnosing and prognosticating Malignant Pleural Mesothelioma(MPM), The clinical ¹⁸F-FDG PET/CT images of nineteen patients, treated in this hospital from October, 2006 to March, 2010, were reviewed. The patients’plasma carcinoembryonic antigen (CEA) was measured，and the maximum standardized uptake value (SUVmax) was determined from the most active pleural lesion in each patient, MPM was histologically confirmed in 17 patients while 2 patients were diagnosed to have benign pleural diseases. The coincidence rate of PET/CT was 89%。Significant differences in SUVmax were found between patients with MPM （11.88±5.39）and those with benign pleural lesions（4.1±0.85）(P=0.005 8，P＜0.01)). The results showed that the intensity of uptake was higher in non-epithelial tumors (SUVmax15.88±3.94) than the epithelial subtype (SUVmax7.4±2.82), with the difference showing a trend towards statistical significance(t=4.56,P＜0.01)). Four patterns of uptake were observed in tumor diseases such as focal, linear, mixed (focal/linear), and encasing, with a significant difference between the intensity of uptake in encasing group （SUVmax16.63±4.51）compared to others types (SUVmax10.61±4.85) (t=3.64, P＜0.01). For different clinical grades, Grade Ⅳ（SUVmax19.83±3.57） was higher than GradesⅡandⅢ（F=7.69, P<0.01). The SUVmax values of the group with CEA≥5 μg/L (SUVmax 14.19±5.15) were significantly higher than the groups with CEA＜5 μg/L (SUVmax 8.6±4.04), the differernce being statistically significant (t=2.39,P＜0.05). The results showed that ¹⁸F-FDG PET/CT is an sensitive technique for diagnosing malignant pleural mesothelioma and the SUVmax is correlated histologically with clinical grades, update types and CEA levels. Poor prognosis was observed for the following cases：non-epithelial subtype; Grad Ⅳ; encasing updated group; and the group with CEA≥5 μg/L. In summary, ¹⁸F-FDG PET/CT should play important roles in diagnosing and prognosticating malignant pleural mesothelioma.