A light guide plate includes a light exit surface, a reflection surface opposite to the light exit surface, at least one light incidence surface connecting to the light exit surface and the reflection surface, and two side surfaces. The reflection surface includes first and second minute projection structures projecting toward interior of the light guide plate, the second minute projection structures being arranged between the first minute projection structures and the two side surfaces of the light guide plate. The first minute projection structures each include at least two side faces coated with a high reflectivity material and forming at least one included angle pointing toward the at least one light incidence surface. The second minute projection structures each include a side face coated with a high reflectivity material and defining two angles, which are less than 90°, with respect to a light incidence surface and a side surface.