Preparation method of grid of transmission electron microscope

The invention provides a preparation method of a grid of a transmission electron microscope. The method comprises that copper-based graphene is cleaned by chloroform, acetone and isopropanol successively; after the organic solvents are all volatilized the copper-based graphene is placed under the water surface with the graphene surface upwards; a micropore array carbon support film is floated at the water surface; the copper-based single-layer graphene scoops up the micropore array carbon support film floated at the water surface from bottom to top, the micropore array carbon support film, the single-layer graphene and the copper base are dried at the room temperature with the copper base surface downwards; the micropore array carbon support film, the single-layer graphene and the copper base are floated in a ferric trichloride with the copper base surface downwards; the composite film is cleaned by hydrochloric acid for multiple times; the composite film is cleaned by pure water for multiple times; a metal grid scoops up the composite film floated at the water surface from bottom to top; and the metal grid is dried. The coverage rate of single-layer graphene of the grid is higher than 70%, and the grid is suitable for preparation of transmission electron microscope samples.