The present invention discloses a method for adjusting the level of galanin in brain, by optic nerve light conduction, comprising the following step: controlling light of different wavelengths, different intensities and different frequencies to illuminate an eye by a light adjustment device, so that galanin receptors in the eye are activated to produce signal, stimulation, and signals transmitted to the hypothalamic visual receiving area via the optic nerve can influence the level of galanin expression in the brain.
