Objective To evaluate 18F-FDG hPET/CT in the diagnosis of postoperative recurrence and metastasis of colorectal cancer. Methods GE HAWKEYE coincidence SPECT was carried out in 81 colorectal cancer patients with suspected recurrence or metastasis after intravenous injection of 259 ~ 298 MBq (7-8 mCi) 18F-FDG. The acquired data were reconstructed using iterative algorithm and attenuation-corrected X-ray. The results were compared with the final diagnosis established by histological examination of resected specimens、and clinical follow-up. Results The sensitivity, specificity, positive predictive value (PPV)and negative predictive value(NPV)was 93% (57/61)、80% (16/20)、93% (57/61)、80% (16/20) for 18F-FDG hPET/CT respectively. For conventional CT the sensitivity, specificity, PPV and NPV was 67% (37/55)、73% (19/26)、84% (37/44)、51% (19/37) respectively; 18F-FDG hPET/CT detected 91 recurrent or metastatic lesions whereas only 46 lesions were detected by conventional CT in 65 patients. Conclusions 18 F-FDG hPET/CT has unique value in the diagnosis of recurrence and metastasis in postoperative colorectal cancer patients which was superior to conventional CT. Combined 18 F-FDG coincidence imaging with localizing CT improves the detection and localization of postoperative recurrence and/or metastasis in colorectal cancer patients.