Light guide plate and preparation method thereof, backlight module and liquid crystal display screen

The invention belongs to the field of optical devices, and discloses a light guide plate and a preparation method thereof, a backlight module and a liquid crystal display screen, the light guide plate is provided with a light-in end face and a light-out face, the light-in end face is one side of the light guide plate corresponding to a backlight source, the light-out face is one side adjacent to the light-in end face, and the light-in end face is provided with a first continuous microstructure; a first area with a non-continuous microstructure and a second area with a second continuous microstructure are arranged on the light-out surface, the non-continuous microstructure is arranged close to one side of the light-in end surface, and one side, far away from the light-in end surface, of the second continuous microstructure is arranged in parallel. According to the light guide plate, the light leakage phenomenon generated in the light path coupling process is avoided, the brightness of the light guide plate is