Peritoneal dialysis utilizes the peritoneum as a semi-permeable membrane and injects peritoneal fluid into the peritoneal cavity through a peritoneal tube to remove toxins and correct electrolyte and acid-base balance disorders through the principle of dispersion, and achieves ultrafiltration and dehydration through the principle of osmosis (glucose is added to the peritoneal fluid to increase the osmolality of the peritoneal fluid) to substitute for the excretory function of the kidneys. The equipment of PD is simpler than hemodialysis, can be operated at bedside, and can avoid sudden changes in fluid balance. Peritoneal dialysis is divided into continuous ambulatory peritoneal dialysis (CAPD, where patients can move freely with the equipment), continuous cyclic peritoneal dialysis (CCPD, with the same advantages as CAPD, where patients rely on the peritoneal wall dialysis machine to perform dialysis at night, and can still work during the day), and intermittent peritoneal dialysis (for acute patients). Generally, 4 to 6 PD sessions should be performed per day, with 2,000 mL of PD fluid infused into each session. Peritoneal dialysis is not dependent on machines, is easy to operate, and does not require special training of personnel, so it is inexpensive and can be carried out in primary care units. Although the indications of peritoneal dialysis and hemodialysis are the same, they have their own advantages and disadvantages, and cannot replace each other. Therefore, appropriate choices should be made according to the patient's primary etiology, condition, and medical and economic conditions, so as to maximize the benefits for the patient. The following conditions should be given priority to peritoneal dialysis: ① elderly, poor cardiovascular system function. ② the establishment of hemodialysis vascular access difficulties. Those who have serious bleeding tendency and cannot do systemic heparinization for hemodialysis. ③ Those who have serious bleeding tendency and can't do hemodialysis with systemic heparinization. ④ Those who have diabetic nephropathy and uremia, adding insulin into the peritoneal cavity can make the blood sugar control better. The following conditions are contraindications to peritoneal dialysis: ① within 3 days after major abdominal surgery. ② Peritoneal adhesions or intestinal obstruction. (iii) Infected peritoneal wall that can not be colonized into the peritoneal dialysis tube. Abdominal tumors, intestinal fistula, diaphragmatic hernia and so on. Strict aseptic operation can cause peritonitis, and repeated episodes of peritonitis can reduce the dialysis area of the abdominal wall and reduce the efficacy of dialysis. In addition, due to the membrane pores on the peritoneum are larger than the pore size on the membrane of the hemodialyzer, so the loss of nutrients from the peritoneal dialysis fluid is more serious than in hemodialysis. Therefore, strict aseptic operation as well as sufficient nutrition is the guarantee for the success of peritoneal dialysis. Susceptibility to peritonitis. Low clearance of small molecules. Protein loss is high and nutrition should be strengthened. Dialysis fluid contains sugar, hyperglycemia, increased lipids and weight gain may occur.