Urinary potassium is measured primarily by the ion-selective electrode method. When performing the urine potassium test, it is necessary to let the patient retain the urine for 24 hours, and then mix the urine well. The ion-selective electrode method is widely used because of the advantages of simple and solid electrode structure, high sensitivity and the ability to overcome color interference. Determination of urinary potassium usually has very important clinical significance. If the urinary potassium concentration is higher than normal, then hypokalemia is likely to occur, and appropriate potassium supplementation is required. If the urine potassium concentration is low, hyperkalemia is likely to occur and prompt diuresis is required to remove potassium. Measurement of urinary potassium can reflect the electrolyte balance in the body, once abnormalities are found, positive dietary adjustments should be made, and appropriate treatment should be carried out in a timely manner in accordance with medical advice to prevent electrolyte disorders from occurring.