Abstract: An operating method and device for showing dynamic wallpapers in mobile systems are provided. In one aspect, the disclosed method includes the steps of: displaying a selected video as the dynamic wallpaper; shrinking the display region of the dynamic wallpaper if a user inputs a shrinking command; and expanding the display region of the dynamic wallpaper if a user inputs an expanding command. In another aspect, the disclosed method includes the steps of creating a new display window for new video playback, wherein the dynamic wallpaper is paused when the new video is under a playback operation. A user may control the dynamic wallpaper and the new display window playing the new video to be shrunk, expanded, and/or moved by touching a screen with different gestures.