The application provides a gate driver circuit and a multiphase intelligent power module. When a first switch unit is closed, a power supply charges a first capacitor and a second capacitor, and a first buffer provides a gate voltage for a first power transistor. The first capacitor can improve the potential of the gate of the first power transistor, so that the first power transistor is turned on; second capacitor can provide a negative turn-off voltage for the first power transistor, and can adaptively convert external voltage into voltage that can drive the power transistor. Moreover, the circuit can be realized easily and the voltage of the first power transistor is stable.