Ultrasound of renal cancer may show uneven echo and tumor blood flow. Renal cancer, also known as renal cell carcinoma, is a malignant tumor originating from the epithelium of renal tubules. Patients may have hematuria, pain, abdominal mass and other manifestations. Doing ultrasound examination, it can be found that the mass usually has no complete envelope, with clear or unclear margins. The echogenicity is uneven when there is hemorrhage, liquefaction, necrosis and calcification within the mass. Color ultrasound can also show that there is pressure and interruption of colored blood flow in the bowed vascular ring of the kidney and irregular vascular branching into the tumor. Blood flow within the tumor is mostly richer, and high resistance and high speed arterial spectra can be measured, and blood flow within the tumor can be large or small, with point-like or strip-like colored blood flow. In addition, there is also ultrasonography. Intravenous injection of ultrasonic contrast agent can improve the echo of blood flow, enhance the Doppler signal, and improve the detection of low-speed and small blood flow. It is suggested that patients with kidney cancer should go to the hospital in time and follow the doctor’s prescription for treatment to avoid delaying the condition.