The present application provides a backlight, a method for manufacturing a backlight, and a display apparatus. The backlight includes at least one lamp plate having a base substrate and a light source on the base substrate, the light source being configured to emit light having a first wavelength; a wavelength selection layer on a side of the light source away from the base substrate; and a wavelength conversion layer on a side of the wavelength selection layer away from the base substrate. The wavelength conversion layer is configured to emit light having a second wavelength under excitation of the light having the first wavelength. The wavelength selection layer is configured to transmit the light having the first wavelength through the wavelength selection layer and reflect the light having the second wavelength.