A backlight source and a thinning method for the same are provided. The backlight source includes: a solid state light source array having a plurality of solid state light sources distributed on the base, a light transmitting unit arranged above the solid state light source array, and a plurality of light adjusting units arranged between the solid state light source array and the light transmitting unit. The plurality of the light adjusting units is arranged above the plurality of solid state light sources to reflect the shallow angle incident light from the solid state light source, thus changes the light intensity distribution of the output light through the light transmitting unit from the solid state light sources from Lambertian distribution to main sides emission.