A level shifter circuit based on the fully integrated GaN SOI platform with high dv/dt immunity and negative rail compatibility was designed. Compared with the traditional level shifter circuits, the low voltage domain of the driving part was consistent with the low voltage domain of the high side part of the circuit through the circuit design, and the negative voltage suppression function was realized. Besides, aiming at the logic signal error caused by the internal capacitor charging and discharging caused by the rising and falling of the half-bridge driving switch node, the part of the circuit on the high side was designed to achieve the ability of immunizing common mode noise. In the 200 V GaN SOI process, the level shift circuit converted the 0-6 V input signal to 200-206 V one. The simulation results show that the level shift circuit has a rise transmission delay of 4.74 ns, a fall transmission delay of 4.11 ns, a compatibility to switch node negative rail to -4 V, and a common-mode noise immunity capability of 100 V/ns.