Objective: To analyze the result of 18F-2-deoxy-2-fluoro-D-glucose-positron emission tomography (FDG-PET) in suspicious primary breast cancer patients and to evaluate its value for the surgery therapy. Methods: Total 36 patients suspected of breast neoplasm were enrolled into the research. The result was compared with the pathology result. The rate of missed diagnosis, the rate of misdiagnosis, the sensitivity and specificity were calculated and analyzed. Results: Compared with the pathology results, the misdiagnosis rate, the rate of missed diagnosis, the sensitivity and specificity of FDG-PET for breast cancer were 0％, 36.36％, 63.63％ and 100％, respectively. To those who had a neoplasm no more than 2 cm in diameter, the rate of missed diagnosis was as high as 41.67 ％. To 33 breast cancer patients, the misdiagnosis rate, the rare of missed diagnosis, the sensitivity and specificity for lymph node metastasis were 18.75％, 41.18％, 58.82％ and 81.25％, respectively. Conclusion: FDG-PET has a perfect specificity and a considerable sensitivity to the primary breast neoplasm and similar to the lymph node metastasis diagnosis. It is an ideal choice for those patients with suspected breast cancer but reluctantly to receive a vulnerarious examination.