A light guide plate, a backlight module, a liquid crystal display module and a liquid crystal display device are disclosed. The light guide plate comprises a light-guide-plate body and a protecting frame. The light-guide-plate body comprises a light-exiting surface and a light-transmitting surface that are opposite to each other, and a plurality of side surfaces connecting the light-exiting surface with the light-transmitting surface. The protecting frame comprises a vertical wall and a horizontal wall extending from the vertical wall to an inner side of the protecting frame. The horizontal wall comprises a first contact surface which is attached to an edge of the light-exiting surface. The vertical wall comprises a second contact surface which is connected with the first contact surface, and the second contact surface is attached to side surfaces of the light-guide-plate body.