A driving module for a driving device of a display system includes a control unit, for generating a control signal according to a polarity signal indicating whether the driving device performs a polarity inversion; a first driving unit, coupled to the control unit, a first voltage source and a second voltage source, for generating a positive output voltage at a first output end according to a first display voltage and charging the first output end via the second voltage source according to the control signal; and a second driving unit, coupled to the control unit, the second voltage source and a third voltage source, for generating a negative output voltage at a second output end according to a second display voltage and discharging the second output end via the second voltage source according to the control signal.