The principle of ultrasonic physiotherapy instrument is to use ultrasound to penetrate deep into the soft tissues, promote local soft tissue blood circulation, accelerate the absorption of inflammation so as to achieve the role of treatment. It has the following hazards: 1, if the ultrasonic treatment time is too long or heat control is not standardized, it will lead to skin or deep soft tissue burns, burns, if the deep soft tissue burns, may lead to deep soft tissue inflammation or even muscle necrosis. 2, may lead to the formation of subcutaneous hematoma, such as poor coagulation function or long-term oral If you are doing ultrasonic physiotherapy for acute inflammatory edema, it may lead to more inflammatory edema and may also cause systemic infection.