The invention provides an image processing device and a method thereof. The image processing device comprises a movement evaluation and compensation unit, a storage unit, an image post-processing unit, and an overdrive unit; the movement evaluation and compensation unit is used for working out an interpolation image by movement evaluation and compensation according to an original image, and outputting two frames of images which are continuous in display order in each cycle; the storage unit is used for storing the original image from the movement evaluation and compensation unit; the image post-processing unit is used for receiving the two frames of images outputted by the movement evaluation and compensation unit in each cycle, performing post-processing and outputting the two frames of images; and the overdrive unit is used for performing overdrive-processing and outputting the two frames of images processed by the image post-processing unit. The device saves a memory of the overdrive unit, realizes the cooperation of an ME/MC unit and the overdrive unit, saves the storage space of the system and reduces the cost of the system.