Abstract: An optical lens, a backlight module and a display device are provided. The optical lens includes a main body, a light-incident surface, a recessed surface and a light-emitting surface. The main body has a top portion and a bottom portion. The light-incident surface is recessed into the bottom portion of the main body. The recessed surface is recessed into the top portion of the main body and is opposite to the light-incident surface, in which the recessed surface has a plurality of prism surfaces, and each of the prism surfaces has a normal line, and directions of the normal lines are different from each other. The light-emitting surface connects the top portion and the bottom portion.