An improved level shift circuit was designed, which used a cross-coupling structure to significantly improve the noise immunity of high voltage gate drive integrated circuits (HVIC) without significantly increasing the circuit complexity. The entire driver was designed in a 035 μm 600 V BCD process. The simulation results show that the driver can achieve up to 125 V/ns of dV/dt noise immunity and allow negative VS voltage overshoot up to -96 V at 15 V supply voltage. In addition, this paper theoretically analyzes the propagation delay of the improved level shift circuit. Compared with the traditional HVIC, the overall propagation delay of the HVIC has been optimized and reduced to about 54 ns.