Normally, the normal blood potassium level is between 3.5 and 5.mmol/L. If the patient’s blood potassium is greater than 5.5 mmol/L, it can be clinically referred to as hyperkalemia. The causes of hyperkalemia are mainly related to the following factors: Firstly, the accumulation of potassium in the patient’s body due to excessive oral or intravenous potassium retention drugs and high doses of potassium supplementation, which can cause hyperkalemia; secondly, severe acidosis, shock and infection may cause disorders of electrolyte metabolism in the body, which may also cause hyperkalemia; thirdly, certain renal diseases such as kidney disease, which can cause hyperkalemia. Third, patients with certain kidney diseases, such as nephritis, may also develop hyperkalemia due to reduced potassium excretion by the kidneys. In patients with hyperkalemia, the main clinical manifestations, including enlarged heart and arrhythmias. Cardiac arrest may occur in patients with severe hyperkalemia. In addition some patients may develop numbness in the limbs. Patients with hyperkalemia may also experience gastrointestinal symptoms, such as nausea, vomiting, abdominal pain, etc. In conclusion, hyperkalemia is a metabolic disorder in which potassium levels exceed normal levels. It has various causes and is a clinical emergency.