The invention discloses an LED backlight source, a backlight source module and a display device, relating to the field of display technology, including: a substrate; a plurality of LED chips, each LED chip includes a first light-emitting surface and at least one second light-emitting surface, the first The light-emitting surface is located on the side of the LED chip away from the substrate, and the plane where the second light-emitting surface is intersects the substrate; a prism-shaped light guide structure with a refractive index of n1 is arranged between adjacent LED chips and located on adjacent LED chips In the space defined by two adjacent second light-emitting surfaces; and, the first medium with a refractive index of n2 filled between the LED chip and the prism-shaped light guide structure, n1>n2, the second light-emitting surface of the LED chip At least part of the light emitted from the surface is transmitted through the prism-shaped light guide structure and then emitted through the light-emitting surface of the LED backlight, and the light-emitting surface is parallel to the plane where the first light-emitting surface is located. In this way, it is beneficial to improve the light utilization rate and light uniformity of the light source.