Provided are a light guide plate and a manufacturing method thereof, a backlight module and a display device, in the field of display technology. The light guide plate includes: a light guide plate body, and a quantum dot film layer on a light exiting surface of the light guide plate body. The quantum dot film layer is prepared from a transparent material mixed with a quantum dot material by nano imprinting. According to the present disclosure, the quantum dot material is mixed into the transparent material, and the quantum dot film layer is formed on the light exiting surface of the light guide plate body by nano imprinting.