The normal value of blood potassium is 3.5-5.5 mmol/L. When the blood potassium concentration is lower than 3.5 mmol/L, it is regarded as hypokalemia and requires potassium supplementation therapy. There are two methods of potassium supplementation: oral potassium supplementation and intravenous potassium supplementation. Oral potassium supplementation is relatively safer and simpler than intravenous potassium supplementation, and does not need to be limited by the concentration and speed of potassium supplementation. The principles of oral potassium supplementation include the following: i. Potassium supplementation should be given only when the blood potassium concentration is lower than 3.5 mmol/L. ii. Second, oral potassium supplementation can choose oral potassium chloride tablets or 10% potassium chloride injection, and the oral dosage can be decided according to the degree of reduction of blood potassium. Third, in the process of oral potassium supplementation, regular monitoring of urine output, renal function and blood potassium concentration is needed to avoid rebound hyperkalemia. Fourth, attention can be paid to consuming more foods with high potassium content, and at the same time, attention should be paid to finding the causes of hyperkalemia.