Abstract: The present invention discloses a temperature control method and a system for a blade shaft of an ultrasonic scalpel based on a temperature distribution function model. The system includes the blade shaft of the ultrasonic scalpel and a transducer that are coupled to each other, and is connected to a generator through a cable. When the blade shaft of the ultrasonic scalpel works, actual temperature of the blade shaft is distributed along a one-dimensional space of the blade shaft. The temperature distribution on the blade shaft is determined by a set of the real-time working feedback parameter, the physical structure feature parameter, and the surrounding environmental parameter of the blade shaft. Each temperature distribution corresponds to a solution of the temperature distribution function, and the function can be approximated by a machine leaning algorithm.