Negative pressure suction device generally has the following several roles: first, for home suction or hospital clinical surgery in the emergency suction sputum, there are elderly people at home when they are too old to effectively cough up sputum, you can use the negative pressure suction device to suction sputum to ensure that the sputum will be sucked out, to keep the respiratory tract unobstructed. Second, for obstetrics and gynecology clearance surgery, if the obstetrics and gynecology abortion to clear the uterus after surgery, you need to use the negative pressure suction device to clear the uterus. Third, due to other surgical procedures, the use of negative pressure suction during surgery can suck out the blood, intra-abdominal fluid and smoke from the electric knife, making the surgical field clearer and reducing the chances of infection. Fourth, for post-operative fluid suction, such as after surgery in order to prevent the leakage of subcutaneous fluid, negative pressure suction can be placed to drain.