The invention discloses a manufacturing process of a metal waveguide microcavity optical coupling structure used for photoelectric functional devices. The manufacturing process can greatly improve the optical coupling efficiency of the photoelectric functional devices. The key point of the manufacturing process is that a transitional substrate material is used to realize preparing the metal structures on the upper and lower surfaces of the film of the functional device; and the film preparation of the functional device and the transfer among different substrate materials can be realized through a two-layer paraffin wax technology. The manufacturing process has wide generality, the thickness of the film of the functional device ranges from hundred nanometer to hundred micrometer, the feature size of the metal optical coupling structure ranges from nanometer scale (electron beam photoetching) to micrometer scale (ultraviolet photoetching), and the responsive incident light ranges from visible to terahertz wave band. The embodiment of a long-wave quantum well infrared detector shows that the manufacturing process can optimize the spectral response of the device and greatly improve the infrared response ratio of the device.