Color ultrasound can not directly check kidney function, check kidney function for blood test is more accurate. Color ultrasound, as an auxiliary examination, has been widely used in clinical practice, with cheap and non-invasive characteristics, but color ultrasound is mainly used for the examination of the morphology of urinary organs, such as size, location, shape, inflammation, stones, tumors, and whether there are deformities, and so on. As to whether the kidney function is normal or not, color ultrasound can’t reflect it directly, but it can indicate it indirectly, because according to the normal situation, if the color ultrasound finds that the kidney size and shape are normal, the kidney function should be normal. If the kidney has serious fluid accumulation and the renal cortex becomes very thin, the renal function should be affected. However, there is no specific objective index to illustrate the kidney function, just according to the common sense inference, there is always a special accidental situation, not as accurate as the blood test to check the kidney function.