An exemplary liquid crystal display device includes a liquid crystal panel configured for displaying images according to external image data. The liquid crystal panel comprising a plurality of sub-pixel regions and a controlling circuit. The sub-pixel regions are arranged regularly, each of the sub-pixel regions having either a positive polarity or a negative polarity when displaying images. The controlling circuit is configured to adjust a common voltage applied to the liquid crystal panel according to a relationship between variations of the common voltage and polarity information of at least a plurality of the sub-pixel regions during operation of the liquid crystal display device.