Disclosed are a method and a device for displaying a video on a mobile terminal. The method comprises: a distance between a display screen of the mobile terminal which is displaying the video and human eyes watching the video being displayed on the mobile terminal is acquired; and according to the acquired distance, the caption font size of the video being displayed on the mobile terminal is adjusted, wherein the caption font size and the acquired distance are in a progressive increase relationship. The technical solution provided in the disclosure achieves the effect that the change in the distance between a display screen of the mobile terminal and a user does not influence the user when watching a caption in a video being displayed on the mobile terminal, and the user experience is friendly.