There are many reasons for long leg hair, which can be divided into physiological factors and pathological factors. 1. Physiological factors: the hormone secretion in the body during puberty is related to the hormone level changes in the body, stimulating androgen will lead to the growth of leg hair; in addition, the degree of body hair is also genetically related to the general parents of individuals with strong body hair will be more obvious leg hair. 2. Pathological factors: may be related to endocrine system diseases, such as polycystic ovary syndrome, there will be menstrual abnormalities, acne, infertility and other symptoms, but also lead to the trunk, limbs and legs hair increase phenomenon. If the leg hair is heavy, patients who are willing to treat it are advised to go to a regular medical institution for consultation and treatment after clarifying the cause of the disease, so as not to delay the condition.