Swollen ankles but not pain, the reasons are mainly the following aspects: First, the emergence of heart failure, heart failure patients will be affected by the body circulation, which will easily lead to the body’s venous blood return abnormal, and then the role of gravity leads to the ankle position in the obvious increase in venous blood, so it is easy to appear ankle swelling, but not pain. Secondly, due to thrombosis of deep veins or peripheral venous vessels, thrombosis will definitely lead to restriction of venous return at the distal end of the limb, therefore, it is easy to have an increase in venous blood flow at the distal end of the limb, which also tends to lead to swelling of the ankle as well as painlessness. Thirdly, due to hypoproteinemia, which is a disease of the liver or kidneys that affects the protein content of the body, this will lead to generalized swelling, especially from the ankle joints to the whole body. Of the three causes, heart failure and hypoproteinemia often lead to bilateral ankle swelling, while venous thrombosis and poor venous return tend to be unilateral.