The present invention relates to the field of display techniques, and discloses a light guide plate and a manufacturing method thereof, as well as a backlight module; the light guide plate comprises a light guide plate body and lattice points, wherein the light guide plate body is provided with a light output surface, and a receiving groove for receiving a light source is formed in a surface of the light guide plate body facing away from the light output surface thereof, and a side surface and a bottom surface of the receiving groove form a light input surface. The lattice points are distributed inside the light guide plate body along a plane parallel with the light output surface; the further the lattice points are distanced from the light input surface, the more densely they are distributed. When the above light guide plate is in use, the light source is situated in the receiving groove, and light emitted from the light source is directed into the light guide plate through the side surface and the bottom surface of the receiving groove. Besides, since the further the lattice points are distanced from the light input surface, the more densely they are distributed, the uniformity of light emitted from the light output surface of the light guide plate body can be ensured; in addition, since the lattice points are located inside the light guide plate body, friction is avoided between the lattice points of the light guide plate and the reflecting sheet of the backlight module, which prolongs the life time of the backlight module.