Objective:To evaluate diagnostic value of PET/CT with 18F-FDG and whole-body bone scintigraphy (BS)with 99mTc-MDP for metastatic bone tumor in patients with malignancies. Methods:A total of 75 patients with malignances,average of 59.85 ± 13.59 years old,were included in this study. All patients underwent PET/CT imaging with 18F-FDG and BS with 99mTc-MDP for two weeks. Based on the diagnostic results of patients,we calculated the sensitivity,specificity,positive predictive value (PPV),negative predictive value (NPV),and accuracy of PET/CT imaging and BS method to detect bone metastasis. Moreover,image features on different body regions were assessed and compared between two imaging methods. Results:There were 34 patients diagnosed with skeletal metastasis among all 75 patients. The sensitivity of PET/CT was 94.1%(32/34) in detecting bone metastasis. The specificity of PET/CT was 95.1%(39/41)The PPV,NPV and accuracy of PET/CT were 94.1%,95.1% and 94.7%,respectively. For BS with 99mTc-MDP,the sensitivity of detecting skeletal metastasis was 91.2%(31/34)and the specificity was 65.9%(27/41). The PPV,NPV and accuracy of BS were 68.9 %,90 % and 77.3 %,respectively. On basis of region analysis,the main abnormal uptakes of 18F-FDG were located in spine,rib and pelvis by PET/CT detection. For BS with 99mTc-MDP,the main lesions were located in rib,spine and bones of limbs. Conclusion:The specificity,accuracy and PPV of PET/CT imaging were higher than those of BS. However,there was no significant difference in sensitivity and NPV between PET/CT imaging and BS.