The invention is applied to the technical field of optics, and provides a method and apparatus for detecting a relation between an evanescent field and Goos-Hanchen displacement, and an optical device. The method comprises the following steps: according to physical meanings of a stress function and a potential field function of light in the evanescent field, obtaining a potential field function of the evanescent field for total-reflection light; through combination with the potential field function of the evanescent field for the total-reflection light, obtaining a wave function of the total-reflection light after perturbation through a Schrodinger equation; and comparing the wave function of the total-reflection light after the perturbation with a wave function of free total-reflection light without an evanescent field effect, and the total-reflection light obtaining momentum having the same momentum property as the evanescent field under the effect of the evanescent field. According to the invention, better regulation and control of the Goos-Hanchen displacement can be realized, and the Goos-Hanchen displacement can be better applied to such fields as optical sensors, all-optical switches, light beam displacement modulators and the like.