Objective　To investigate the importance of CT diagnosis and differential diagnosis in Wilms′ tumors of children.Methods　45 cases of Wilms′ tumors confirmed by clinical and pathology were retrospectively analyzed,CT characteristics of Wilms′ tumor,renal carcinoma(2 cases),renal rhabdomyosarcoma(1 case)in children were discussed.Results　Wilms' tumors appeared in solid masses in 34 cases (76%),cysticsolid masses in 9 cases(20%),cystic masses in 2 cases (4%),7 cases (15.6%)had thrombosis in renal vein or IVC.Renal carcinoma shared the same appearance with Wilms′ tumor in image.Rhabdoid tumor of kidney appeard as cystic-solid mass with lineal calcification and subcapsular fluid accumulation.Conclusion　Wilms′ tumor is the most popular malignant renal tumors in children.It is originate from renal parenchyma,and likely to invade renal pelvis.Hemorrhhage,necrosis or cystic formation in tumor is common.They are difficult to be distinguished from renal cell carcinomas in radiology.Rhabdoid tumor of kidney is rare and has characteristic features on CT.