Kidneys are very important to everyone, and it is really unimaginable to imagine what would happen if a person did not have them. Many people understand this, so they know how to protect themselves very well in life and will not let their bodies have any problems. But some people are not like this, they squander their youth and overdraw their body recklessly. As a result, they lead themselves to have chronic renal failure. So, what harm will occur in chronic renal failure? Kidney reserve capacity loss period. Also known as chronic renal failure compensatory period. In this period, the glomerular filtration rate is reduced to 30–60 ml/min, and the blood creatinine and urea nitrogen tests are normal or mildly high. In this period, although the renal reserve capacity is lost, the ability of the kidneys to excrete metabolic wastes and regulate the water-electrolyte and acid-base balance is still able to maintain the stability of the internal environment of the organism. Azotemia stage. In this period, the glomerular filtration rate is 25 ml/min, there is azotemia, i.e., the blood creatinine and urea nitrogen are elevated, and there is a mild impairment of renal concentrating function, and the patient may have mild clinical symptoms, such as polydipsia, nocturia, mild anemia, etc., which is easy to be overlooked. In this period, if the body encounters additional loads such as blood volume insufficiency, infections, nephrotoxic drugs, renal function can deteriorate rapidly, and renal failure or even uremia occurs. The residual glomerular filtration rate is less than 10 – 15 ml/min, which is the advanced stage of chronic renal failure. Symptoms of renal failure are more obvious, and multiple systems in the body are damaged with corresponding symptoms, especially gastrointestinal, cardiovascular and central nervous system symptoms are more obvious. Blood creatinine, urea nitrogen significantly increased, water electrolyte serious imbalance, obvious metabolic acidosis, hyponatremia and hyperkalemia, blood calcium significantly decreased, blood phosphorus increased, easy to endanger the patient’s life. In the early stage of renal failure due to shock and trauma, the glomeruli are mostly unchanged, the proximal tubules have vacuolar degeneration, the cilia of tubular epithelial cells are detached, and in the severe cases, there can be necrosis of renal tubular cells, and there is inflammatory cell infiltration around the necrotic area, and the lumen of the distal tubules and collecting tubules is dilated, and there is a tubular pattern in the tubular lumen. We all have to be diagnosed by doctors to give a good answer to the condition of renal failure, because the condition is different will be different in the treatment. Therefore, when the phenomenon of renal failure occurs, we should not treat it by ourselves, otherwise other problems will occur.