Objective: To explore the characteristics of the primary ureteral carcinoma (PUC) and discuss the value of spiral CT (SCT) in the diagnosis of PUC. Methods: The SCT findings of the primary ureteral carcinoma in 16 cases were analyzed and compared with the histopathological diagnosis and staging. Results: The transverse diameters of the lesions were 1.0–2.1 cm, and the longitudinal lengths were 1.5–15.2 cm. There were no statistically significant differences (P>0.1) in diam- eters and lengths among the low staging group (pT0–T2) and the high staging group (pT3–T4). The average CT value of the lesions was 43 HU on plain scanning, and 73 HU on CE scanning. The increment was 30 HU. The lesions were clearer on CE scanning. Curved planar reconstruction (CPR) could show the entire course of the urinary tract. Among 6 cases of pT3 stage, CT gave a correct diagnosis in 1 case. For 2 cases of pT4 stage, CT gave correct diagnoses in both cases. Conclusion: The carcinomatous lesions spread along the ureter. The longitudinal length of each lesion is longer than its transverse diameter. Tumor cannot be staged merely according to its diameter and length. CT is difficult to differentiate stage T0–T3, while for stage T4, CT diagnosis is accurate. Contrast enhancement CT scanning has the confirming and differentiating roles. CPR offers direct and easy observing images for clinical doctors. Objective: To explore the characteristics of the primary ureteral carcinoma (PUC) and discuss the value of spiral CT (SCT) in the diagnosis of PUC. Methods: The SCT findings of the primary ureteral carcinoma in 16 cases were analyzed and compared with the histopathological Diagnosis and staging. Results: The transverse diameters of the lesions were 1.0-2.1 cm, and the longitudinal lengths were 1.5-15.2 cm. There were no significant significant differences (P> 0.1) in diam- eters and lengths among the low staging groups The average CT value of the lesions was 43 HU on plain scanning, and 73 HU on CE scanning. The increment was 30 HU. The lesions were clearer on CE scanning (pT0-T2) and the high staging group (pT3-T4) Among 6 cases of pT3 stage, CT gave a correct diagnosis in 1 case. For 2 cases of pT4 stage, CT gave correct diagnosis in both cases. Conclusion: The carcinomatous lesions spread along the ureter. The longitudinal length of each lesion is longer than its transverse diameter. Tumor can not be staged merely according to its diameter and length. CT is difficult to differentiate stage T0-T3, while for stage T4, CT diagnosis is accurate. enhancement CT scanning has the confirming and differentiating roles. CPR offers direct and easy observing images for clinical doctors.