This application discloses a drive circuit of a bridge arm switching transistor, a drive circuit, and a power converter. The bridge arm switching transistor includes a first switching transistor and a second switching transistor. A first terminal of the first switching transistor is connected to a power supply, a second terminal of the first switching transistor is connected to a first terminal of the second switching transistor, and a second terminal of the second switching transistor is grounded. The drive circuit includes a low-voltage region and at least two high-voltage regions isolated which include a first high-voltage region and a second high-voltage region. A semiconductor device configured to drive the second switching transistor is disposed in the low-voltage region. P-type semiconductor devices are disposed in each of the first high-voltage region and the second high-voltage region, and the P-type semiconductor devices are configured to drive the first switching transistor.