The hazards of sitting cross-legged on the human body mainly include damage to the knee cartilage, injury to the seamstress muscle and varicose veins and so on. 1. Knee joint cartilage damage: when the legs sit in a cross-legged manner will lead to excessive bending of the knee causing great pressure, the pressure inside and outside of the knee is not uniform easily lead to cartilage damage of the knee, when the legs sit in a cross-legged manner for a long time or sit in the posture of inappropriate, it is also easy to aggravate the damage to the knee. 2. Suture muscle injury: when sitting with legs crossed, the suture muscle will be in a tense state for a long time, when it exceeds the normal load, it is easy to cause chronic injury to the suture muscle. 3. Varicose veins: Standing for a long time is the most common cause of varicose veins, but sitting with legs crossed will also compress the veins of the lower limbs, resulting in restricted blood flow and varicose veins. It is recommended to change the habit of sitting with legs crossed as soon as possible.