The present invention discloses a head-mounted display and a video data processing method thereof. The head-mounted display comprises: a video input module, a distortion processing module and a video output module. The head-mounted display divides each image frame in a video into a plurality of image blocks of symmetry according to a graphic correspondence of a distorted image after a distortion processing, performs a distortion processing of any one of the image blocks, and obtains data of the current image frame after the distortion processing according to the graphic correspondence.