Swelling below the knee is generally called moderate edema, the cause can be caused by a variety of diseases.1, heart failure: especially the right heart failure, lower limb edema can occur after activity, and can be reduced after rest. The cardiac function can be clarified by checking the cardiac ultrasound, and if necessary, cardiotonic, diuretic and other medications can be given.2, poor vascular reflux: the lower extremity arterial ultrasound can be clarified, such as the lower extremity occlusion. It can be treated by surgery or with oral medication to improve circulation in the lower limbs.3, nephritis or nephrotic syndrome: often caused by hypoproteinemia, which can be alleviated by the application of immunosuppressants and the application of drugs such as volume expansion and diuresis.4, thyroid disease: thyroid dysfunction is often found in middle-aged women, and it can be improved by the supplementation of thyroid hormones.