The invention discloses a backlight source and a display device. The backlight source comprises a first light source layer and a second light source layer. The first light source layer is arranged at the light emergent side of the second light source. The light emergent side of the first light source is back to the second light source layer. The first light source layer comprises multiple first light source strips which are arranged along a first preset direction. A light-transmitting area is arranged between any two adjacent first light source strips in the preset direction. The first light source layer emits light and is used for emitting light in 2D display and does not emit light in 3D display. The second light source layer does not emit light in 2D display and emits light in 3D display. According to the backlight source, the corresponding display device can be supported for switching between 2D display and 3D display.