Provided are a method and circuit for controlling heat generation of a power transistor, in which the power transistor can be protected by preventing heat generation of the power transistor by using a metal-insulator transition (MIT) device that can function as a fuse and can be semi-permanently used. The circuit for controlling heat generation of a transistor includes a metal-insulator transition (MIT) device in which abrupt MIT occurs at a predetermined critical temperature; and a power transistor connected to a driving device and controlling power-supply to the driving device, wherein the MIT device is attached to a surface or heating portion of the transistor and is connected to a base terminal or gate terminal of the transistor or a surrounding circuit from a circuit point of view, and wherein when a temperature of the transistor increases to a temperature equal to or greater than the predetermined critical temperature, the MIT device reduces or shuts off a current of the transistor so as to prevent heat generation of the transistor.