The invention discloses a camera exposure method. The method includes: dividing frames input by a camera sensor into multiple photosensitive units according to a default mode; calculating first brightness of the photosensitive unit with the highest brightness in the frames; calculating first average brightness of all the photosensitive units in the frames; acquiring exposure brightness according to the first brightness of the photosensitive unit with the highest brightness in the frames and the first average brightness of all the photosensitive units of the frames; processing and displaying the frames input by the camera sensor according to the exposure brightness. The invention further provides a camera exposure device adopting the camera exposure method and a mobile terminal. By the above mode, the technical problem that the center focus-highlighting frames are unclear in shooting can be solved.