Heavy legs and weakness are common in two conditions: 1. bilateral lower limb edema; 2. hypokalemia. If caused by edema of both lower extremities, it can be seen in heart disease, liver disease, kidney disease and abnormal thyroid function. If it is caused by heart disease, it can be accompanied by chest tightness and breathlessness, which requires cardiac strengthening and diuretic treatment. If the disease is caused by kidney disease, diuresis alone cannot be used because diuresis alone can aggravate thrombosis in nephrotic syndrome, and renal puncture biopsy should be performed to clarify the pathological type if necessary. If the disease is caused by liver disease, we can perform virus serology and quantitative virus examination to clarify the diagnosis, and if necessary, antiviral treatment, intravenous infusion of human albumin, and symptomatic treatment such as volume expansion and diuresis. If the disease is caused by hypokalemia, it can be seen in patients with poor diet or massive diarrhea, and leg weakness can be reduced by actively improving electrolyte metabolism disorders.