The invention relates to a light guide plate which comprises a bottom surface, a light emitting surface and a side face, wherein the bottom surface is provided with scattering dots; the light emitting surface is arranged opposite to the bottom surface; and the side face is connected with the bottom surface and the light emitting surface. The light emitting surface of the light guide plate is provided with a reflection part. The reflection part is arranged in the position of the light emitting surface of the light guide plate, opposite to the center of the bottom surface, and is sunken into the light guide plate. The scattering dots are distributed on a plurality of circular rings which use the center of the bottom surface of the light guide plate as a circle center. The scattering dots are uniformly distributed in the circular ring, and the quantity of the scattering dots in the circular ring satisfies the following relationship formula: e= absolute value of 4, wherein e is the quantity of the scattering dots; r is the radius of the circular ring, and is not less than 4 millimeter; and a1, a2 and a3 are constants, a1 is not less than 0.05, but is not more than 0.1, a2 is not less than 6, and a3 is not more than 12. In addition, the invention also provides a backlight module using the light guide plate.