The invention provides a reflective plasma nanostructure photoswitch and a preparation method thereof. The reflective plasma nanostructure photoswitch comprises a polarization modulation device for changing the polarization directions of incident light, and a plasma nanostructure. The plasma nanostructure comprises a metal film on the bottom layer, a dielectric film on the middle layer, and multiple metal nano-rings distributed on the upper surface of the dielectric film. The metal nano-rings are symmetrically distributed and form a periodically-arranged metal nano-ring array. The plasma nanostructure formed by the metal film, the dielectric film and the metal nano-rings in an arrayed mode is utilized, when the incident light irradiates the plasma nanostructure in different polarization directions, the incident light can be completely reflected or fully absorbed, therefore, control over the on or off state of the incident light is formed, compared with a transmission type switch which has the problem of the low extinction ratio, the reflective plasma nanostructure photoswitch has the larger extinction ratio coefficient, and the preparation method is simple and easy to integrate.