The invention discloses a drive circuit of a switch device. The invention adopts the transformer isolation drive, wherein two transformers are provided, the primary sides of which are respectively connected with two drive modulators; the input end of the high frequency carrier signals, the input end of the drive signals are connected with the input end of a first drive modulator; the input end of the drive signals is connected with a reverser and connected with the input end of a second drive modulator with the high frequency carrier signals; a first auxiliary side of the first transformer is connected with a power supply circuit which provides the required voltage to the switch device for on/off in the high level signal period of the drive signals; a first auxiliary side of a second transformer is connected with a voltage release circuit for releasing the on voltage of the switch device into a voltage in the low level in a low level period of the drive signals. Therefore, a geminate transistor amplifying circuit in the traditional transformer isolation drive is not required, therefore the pushing power is large, and no optical couple isolation element is adopted, thereby prolonging the service life.