Various primary or secondary chronic kidney diseases can impair renal function. When the kidney disease progresses to a certain level and the kidney function decreases to only 25% of normal, even if the underlying disease has stopped its activity, the kidney function will continue to decrease continuously through some common damage mechanism until uremia occurs. This is the objective law of disease development, and there is no effective cure at home and abroad. With the progressive decompensation of the kidney’s toxin excretion function, the patient’s body retains more and more uremic toxins, and the long-term accumulation of uremic toxins can gradually produce irreversible damage to other important organs (such as the heart, lungs, nervous system, bones, etc.), with catastrophic consequences. This is because scientific studies have found that damage to extra-renal organs is the most important cause of long-term survival and quality of life in maintenance dialysis patients. In other words, for uremic dialysis patients, the key to improving their long-term survival and quality of life lies in avoiding or mitigating damage to other important organs outside the kidney as much as possible. Since, in the final analysis, everything is caused by renal decompensation, but for true end-stage renal disease (uremia), there is no “magic pill” that can repair the kidneys and reverse the disease, so it is important to carry out renal replacement therapy at the right time to help the kidneys remove the uremic toxins produced by the body every moment and control the accumulation of toxins in the body. It is the most effective measure to avoid or reduce the damage of other important organs outside the kidney, and it is also a prerequisite to ensure that patients with uremia “live long and well”. The current renal replacement therapy mainly includes hemodialysis, peritoneal dialysis and kidney transplantation. Other techniques such as oral gastrointestinal dialysis solution and Chinese medicine enemas have been largely eliminated because of their low efficacy and side effects. So when should uremic patients start renal replacement therapy? At present, the best protocol recognized by international nephrologists is when chronic kidney disease is in CKD stage 4 (estimated glomerular filtration rate, i.e., eGFR, decreases to 29 ml/min/1.73m2 to 15 ml/min/1.73m2), patients should receive education about renal replacement therapy, understand the advantages and disadvantages of various renal replacement therapies, and choose the future renal replacement therapy in the light of their specific conditions. The patients should be educated about renal replacement therapy, understand the advantages and disadvantages of various renal replacement therapies, choose the renal replacement therapy they will receive in the future according to their specific conditions, and make appropriate preparation. When chronic kidney disease is in CKD stage 5, i.e., eGFR is less than 15 ml/min/1.73m2, the nephrologist should decide when and what method to start renal replacement therapy based on the patient’s specific situation, weighing various factors, including primary disease, complications, uremic symptoms, nutritional status, vascular conditions, blood pressure and blood sugar control, previous surgical history, age, economic situation, medical conditions, etc. replacement therapy. If some of the complications are severe, renal replacement therapy can be started early at the right time even if the eGFR is greater than 15 ml/min/1.73m2.