A display apparatus having a displaying part, includes a video processing part to process an input video signal into a format which can be displayed on the displaying part, and a controlling part to determine whether a video image displayed on the displaying part is a still image, and if it is determined that the video image is the still image, to control the video processing part to display the video image according to the input video signal and a predetermined after-image prevention image alternately on the displaying part. Thus, the present concept provides a display apparatus which is capable of removing an after-image effect occurring in a display panel effectively, and a control method thereof.