A method for increasing antioxidant content in plants, which includes: (a) placing at least one light transmissive material for adjusting or retaining light transmittance at certain wavelengths between a light source and photosynthesis receptors of the plants； and (b) passing a light emitted from the light source through the light transmissive material, wherein the light transmissive material adjusts or retains at least two of the following wavelength sections: the light transmittance at a section from 340 nm to 500 nm is 65% or less； the light transmittance at a section from 500 nm to 600 nm is 60% or less； and the light transmittance at a section from 600 nm to 850 nm is 83% or less.
