Abstract: Taking Cr₂AlC coating as an example, a preparation method of transmission electron microscope specimen based on micropillar was introduced in detail. First, the high-intensity ion beam was used to remove the material around the micropillars together with the area below the protective layer to form a micron sheet with a length of 10 μm, a depth of 6 μm, and a thickness of 1 μm. Finally, the ion beam was used to thin the micron sheet to a thickness that could be observed by the transmission electron microscope. The sample preparation process needed to deposit a protective layer on both sides and the top of the micron column to be thinned to avoid processing damage to the micron column during the thinning process, thereby obtaining a high-quality transmission electron microscope sample.