CT examination is an important element of kidney cancer imaging. When malignant tumor is found in kidney, the solid soft tissue in kidney can protrude outward, presenting lobulated shape, squeezing and deforming renal pelvis and calyces, and presenting destruction-like signs when the edges are invaded. Kidney cancer is prone to cystic transformation, hemorrhage, necrosis, calcification, etc., and uneven density, with necrosis being the most common. When the renal parenchyma is strengthened with high density and the tumor shows relatively low density, it can clearly show the boundary between normal tissues and renal cancer, and it can also better show the relationship between renal tumor and renal envelope, which can determine the degree of development and relationship for the disease. It is also of good diagnostic significance to observe whether there is cancerous thrombus in renal pelvic vein and inferior vena cava during enhancement scan, which is valuable for tumor staging.