Calf swelling after walking is caused by poor blood return to the lower extremities and can occur in the normal population, mostly in middle-aged women. It is common in certain pathological conditions, such as lower extremity venous thrombosis, lower extremity varicose veins, and in patients with lower extremity venous valve malfunction. Patients mentioned above should actively treat the primary disease, and the leg swelling may disappear after the cause is removed. It is also important to avoid prolonged sitting, standing, or prolonged walking to avoid aggravation of symptoms.