A data driving circuit, used to drive display devices, comprises a digital-to-analog current converter (DAC), a reset circuit connected to the output terminal of the DAC for resetting the output potential of the DAC to a specific gray scale potential, and plural stages of data driver units connected to the output terminal of the DAC and the reset circuit to drive data lines of the display devices. Each of the data driver units comprises a sample-holding circuit and a control circuit.