The ultrasonic knife beauty is the use of ultrasound accumulation of heat energy principle, through the fractional cluster heat transfer mode, directly to the skin fascia layer, stimulate collagen and elastic fibers constantly new, so that the skin is elastic, white and tender. The side effects of ultrasonic knife in the use of the following: 1, during the ultrasonic knife treatment, may feel the local skin or subcutaneous pain, the degree of pain varies from person to person. Therefore, it is conventional to apply local numbing cream, the main role of the external numbing cream is to reduce the pain of the epidermis; 2, after the end of treatment, individual candidates will have a local swelling, or even mild redness; 3, when the ideal doctor is not found to operate, and the operation is not regular, the potential danger is greater. Because some skin has dense nerves and blood vessels under the skin, ultrasonic knife treatment needs to be avoided. Ultrasonic knife can form a line of multi-point agglutination under the skin, sometimes destroying the nerve endings and blood vessels under the skin, which may cause local sensation of the patient, or even local innervation failure, numbness, or facial paralysis in serious cases. Therefore, it is recommended that ultrasound treatment must go to a regular hospital.