This specification specifies the requirements and mass assurance regulations for metal outer reflection coatings. It is applicable to the acceptance of metal silver, aluminum and JINHE copper outer reflection coatings on Optical inspection parts. A series of standard documents are quoted, including Optical inspection parts surface defects, military equipment environmental test methods, etc. Requirements include Optical Property, coating area and film mass. Optical Property requires white light reflection ratio to reach a certain value, such as aluminum film not less than 87%, silver film not less than 95%; Light spectrum reflection ratio also has corresponding requirements. The coating area should comply with the provisions of product drawings or technical documents. Appearance of the film layer is not obviously damaged, such as stripping, peeling, crazing and fog.