1. A method for image taking brightness control, comprising: acquiring a preview image frame, and determining a brightness level n of each pixel in the preview image frame; dividing the preview image frame into M class areas according to the determined brightness level n of each pixel; determining an exposure adjustment level required when the preview image frame is taken according to the distribution condition of detail features comprised in each class area in the preview image frame; and adjusting a pre-acquired exposure parameter according to the determined exposure adjustment level, and taking an image according to the adjusted exposure parameter.