The disclosure is related to a light guide plate, comprising a first side, a second side opposite to the first side, a third side, and a light-entering side opposite to the third side; wherein each of the first side, the second side and the third side is provided with a reflector structure respectively. The disclosure is further related to a backlight module comprising the light guide plate. The reflector structures reflect the light into the light guide plate when the light is indicent to the side having the reflector structures from the light-entering side. The light guide plate increases the light utilization efficiency without causing the bright band appearing at the side of light guide plate at the same time and thereby increases the emitted light uniformity of the backlight module.