A liquid crystal display (LCD) driver has the characteristic that using a voltage-switching control circuit to receive the liquid crystal positive voltage and the segment positive voltage generated by the driving voltage generating circuit. The voltage-switching control circuit respectively switches the liquid crystal positive voltage and the liquid crystal negative voltage to input to the common driver in different frame stages such that only one of the liquid crystal positive voltage and the liquid crystal negative voltage exists at the same time. Therefore, for the choice of the semiconductor manufacturing process for the LCD driver, the process with only half of the voltage-resistant can be chosen according to the original design of the circuit, and the supplying for the voltage needed by the segment driver and the common driver is unchanged.