OBJECTIVE: To analyze the CT manifestation and diagnostic value of cystic kidney cancer and improve the diagnostic accuracy of cystic kidney cancer. METHODS: The clinical manifestations, CT examinations and pathological data of 11 cases of cystic kidney cancer were retrospectively analyzed, and all 64-row spiral CT plain scan and three-stage enhancement scan were performed, together with multi-planar reconstruction in coronal and sagittal positions. Results: All 11 cases of cystic kidney cancer showed cystic or cystic solid masses, regular or irregular, of different sizes, with cystic wall thickening, wall nodules in 9 cases, intra-tumoral segregation in 4 cases, and cystic wall calcification in 4 cases. The cystic wall and the intracapsular compartment were unevenly thickened, and enhancement of the cystic wall, intracapsular compartment and wall nodules was seen after enhancement, and most of them had a “fast-in-fast-out” feature. Multiplanar reconstruction images showed clearer details of the tumor and its relationship with surrounding structures. Conclusion: Cystic renal carcinoma has typical CT manifestations, and multi-phase enhancement scan and multiplanar reconstruction of multi-layer spiral CT can help to make a definite diagnosis, but it needs to be differentiated from other cystic lesions in the kidney. 【Key words】 Cystic renal cell carcinoma; CT; diagnosis Lu Yuhua, Hong Qi, Liang Zonghui, Ye Tao, Zhang Shiyu. Diagnosis and differential diagnosis of cystic renal carcinoma by multi-row spiral CT. CT Theory and Application Research 2013; 22(3): 523-530. (Corresponding author)